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• Pyrolysis combined with ball milling is proposed to upcycle SG from retired LIBs. • Pyrolysis at 500 °C leads to about 82.2 % PVDF dissociation in TG. • Ball milling assisted by urea produces abundant graphite flakes at the edge of MG. • High purity and unique edge structural features of MG result in exceptional capacity. Vast quantities of anode graphite from waste lithium ion batteries (LIBs), as a type of underrated urban mine, has enormous potential to be exploited for resource recovery. Herein, we propose a benign process integrating low-temperature pyrolysis and mechanochemical techniques to upcycle spent graphite (SG) from end-of-life LIBs. Pyrolysis at 500 °C leads to about 82.2 % PVDF dissociation in thermal treated graphite (TG). Solid-phase exfoliation via ball milling assisted by urea successfully produces abundant graphite flakes and a small amount of monolayer graphene nanosheet at the edge of mechanochemically processed graphite (MG). Subsequent rinsing removes the residual LiF salts. High purity and unique edge structural features of the as-prepared MG offer more active sites and storage reservoir for intercalation and de-intercalation of lithium ions, resulting in enhanced lithium-ion diffusion kinetics, excellent reversible specific capacity and desirable rate capability. Inspiringly, MG exhibits a remarkably enhanced initial specific charge capacity of 521.3 mAh g−1 during the first charge–discharge, and only declines from 569.9 mAh g−1 to 538 mAh g−1 with slight attenuation after 50 consecutive cycles at 0.1 A/g, indicating satisfactory cycle stability. Additionally, the purification and reconstruction mechanism for MG have been illustrated in detail. This study offers a green strategy to reconstruct and upgrade anode graphite from LIBs, which can realize sustainable waste management. [ABSTRACT FROM AUTHOR]

The massive volume dilation, unsteady solid electrolyte interphase, and weak conductivity about Si have failed to bring it to practical applications, although its potential capacity is up to 4200 mAh g−1. For solving these problems, novel binary regulated silicon–carbon materials (Si/BPC) were done by a sol–gel procedure combined with single carbonization. Analytical techniques were systematically utilized to examine the effects of element doping at several gradients on morphology, structure and electrochemical properties of composites, thus the optimal content was identified. Si/BPC preserves a discharge specific capacity of 1021.6 mAh g−1 with a coulomb efficiency of 99.27% after 180 cycles at 1000 mA g−1, within the upgrade than single-doped and undoped. In rate test, it has a specific capacity of 1003.2 mAh g−1 at a high current density of 5000 mA g−1, quickly back towards 2838.6 mAh g−1 at 200 mA g−1. The inclusion of B and P elements is linked to the electrochemical characteristics. In the co-doped carbon layers, the synergistic impact of doping B and P accelerates the diffusion kinetics of lithium ions, boosts diffusion rate of Li+, offers low electrochemical impedance (45.75 Ω). This brings more defects to provide transport carriers and induces a substantial amount of electrochemically active sites, which fosters the storage of Li+, thus making silicon material electrochemically more active and potential. [ABSTRACT FROM AUTHOR]

Despite significant potential as energy storage materials for electric vehicles due to their combination of high energy density per unit cost and reduced environmental and ethical concerns, Co‐free lithium ion batteries based on layered Mn oxides presently lack the longevity and stability of their Co‐containing counterparts. Here, a reduction in this performance gap is demonstrated via chemical doping, with Li1.1Ni0.35Mn0.54Al0.01O2 achieving an initial discharge capacity of 159 mAhg−1 at C/3 rate and a corresponding capacity retention of 94.3% after 150 cycles. The nanoscale origins of this improvement are subsequently explored through a combination of advanced diffraction, spectroscopy, and electron microscopy techniques, finding that optimized doping profiles lead to an improved structural and chemical compatibility between the two constituent sub‐phases that characterize the layered Mn oxide system, resulting in the formation of unobstructed lithium ion pathways between them. A structural stabilization effect of the host compound is also directly observed near the surface using aberration corrected scanning transmission electron microscopy and integrated differential phase contrast imaging. [ABSTRACT FROM AUTHOR]

A carbon superstructure material (PTA-700) was synthesized by a simple self-assembly method and one-step carbonization, and showed remarkable high energy and long cycle life stability in lithium/sodium ion half battery. [Display omitted] Due to abundant resources and low prices, biomass-derived carbons as anodes for lithium ion batteries (LIBs) and sodium ion batteries (SIBs) have been widely reported. However, it is still a challenge to design a biomass-derived carbon material that has immunity to environmental influences, stable chemical composition and controllable morphology. In this paper, tannic acid (TA) as a precursor is first reported to synthesize rod structures with abundant mesopores and defects (PTA-700). These features can provide more active sites and space for lithium and sodium ions storage, which is conducive to lithium and sodium ions transfer. Excellent electrochemical performance is observed in LIBs (535 mAh/g after 100 cycles at 0.1 A/g) and SIBs (114.0 mAh/g after 3000 cycles at 1 A/g). Kinetics analysis and density functional theory (DFT) calculations were carried out to further analyze the superior lithium and sodium ions storage performance of PTA-700. More importantly, PTA-700 solves many problems faced by traditional biomass-derived carbons in commercialization. Our work suggests an effective way to develop high-performance biomass-derived carbon anode materials for LIBs and SIBs. [ABSTRACT FROM AUTHOR]

[Display omitted] Polymer materials containing C 6 rings and C O become promising electrode materials for high-performance lithium ion batteries (LIBs). However, the poor electronic conductivity severely restricts its further application. Herein, we design and construct a pyromellitic dianhydride anhydride anthraquinone/reduced graphene oxides (PMAQ/rGO-40) composite as an anode material for LIBs. The PMAQ is uniformly wrapped by conductive rGO nanosheets. The PMAQ/rGO-40 electrode without additional conductive agents displays a discharge capacity of 253 mAh g−1 over 3000 cycles under 2A g−1, which is higher than that of the PMAQ electrode with conductive agents. Meanwhile, a capacity of 196 mAh g−1 is achieved under 5A g−1. The enhanced cycling performance and rate ability are attributed to the rGO conductive network, which promotes electronic transport capability. In addition, the lithium ion storage mechanism and kinetics in the PMAQ/rGO-40 are investigated. The excellent electrochemical performance shows the potential application of the PMAQ/rGO composite anode material for high performance LIBs. [ABSTRACT FROM AUTHOR]

Due to their safety and sustainability, polysaccharides such as cellulose and chitosan have great potential to be the matrix of gel polymer electrolytes (GPE) for lithium-based batteries. However, they easily form hydrogels due to the large numbers of hydrophilic hydroxyl or amino functional groups within their macromolecules. Therefore, a polysaccharide-based amphiphilic gel, or organogel, is urgently necessary to satisfy the anhydrous requirement of lithium ion batteries. In this study, a PEGylated chitosan was initially designed using a chemical grafting method to make an GPE for lithium ion batteries. The significantly improved affinity of PEGylated chitosan to organic liquid electrolyte makes chitosan as a GPE for lithium ion batteries possible. A reasonable ionic conductivity (1.12 × 10−3 S cm−1) and high lithium ion transport number (0.816) at room temperature were obtained by replacing commercial battery separator with PEG-grafted chitosan gel film. The assembled Li/GPE/LiFePO4 coin cell also displayed a high initial discharge capacity of 150.8 mA h g−1. The PEGylated chitosan-based GPE exhibits great potential in the field of energy storage. [ABSTRACT FROM AUTHOR]

[Display omitted] • MXene was used as conductive substrate to reinforce the structural stability of Sb@C. • The MXene and carbon can spatially confine the Sb particles during cycling. • The MXene-Sb@C shows better lithium storage properties than the Sb@C composite. • The assembled Li ion full cell delivers a maximum energy density of 381.2 Wh kg−1. Antimony (Sb) is recognized as a potential anode material for lithium-ion batteries due to its high theoretical capacity and adequate working potential. However, its application is hindered by the significant volume expansion during lithiation and low intrinsic conductivity, leading to considerable capacity fading and reduced rate capability. Herein, a unique MXene-reinforced Sb@C (MSC) nanocomposite is constructed via in-situ growing Sb-MOF over the conductive MXene substrate, followed by annealing. MXene substrate and MOF-derived carbon layer coupling effectively creates a continuous and conductive framework, encapsulating Sb nanoparticles. This unique architecture mitigates volume expansion, prevents particle aggregation, and enhances interfacial charge transfer, significantly improving the lithium storage performance of the MSC nanocomposite over its Sb@C (SC) counterpart. The MSC nanocomposite achieves a high capacity of 625 mAh g−1 at 100 mA g−1, superior rate capability of 305 mAh g−1 at 10 A g−1, as well as excellent cycling stability with a capacity retention of 84.4 % over 2000 continuous cycles. Additionally, a lithium-ion full batteries with MSC anode and LiFePO 4 cathode demonstrates a capacity of 168.9 mAh g−1 at 100 mA g−1 and a maximum energy density of 381.2 Wh kg−1 based on the cathode mass, illustrating its promising potential for constructing high-performance lithium ion batteries. [ABSTRACT FROM AUTHOR]

The present work demonstrates the solvent‐free, highly flexible, self‐supporting crosslinked network polymer electrolyte membranes with decent ion conductivities and stable battery performance (in terms of rate capability and cycle stability) at ambient temperatures. The network polymer electrolyte membranes are prepared by "thiol‐epoxy" and "thiol‐ene" (co)polymerization using pentaerythritol tetrakis(3‐mercaptopropionate) (PEMP) and terminal‐functionalized poly(ethylene glycol) (PEG). The network polymer electrolyte membranes contain small amounts of solvated ionic liquids (equimolar mixture of tetraglyme and lithium salt) at different lithium salt molar concentrations. The obtained membranes display remarkable homogeneity and high amorphous characteristics, good mechanical robustness, high thermal stability, wide electrochemical stability (>4.20 V vs Li/Li+), and superior lithium ion transference number (tLi+ = 0.20–0.50). The electrochemical and spectroscopic study of the network polymer electrolyte membranes reveals the influence of solvated ionic liquid on the ion conduction, mechanical, thermal, and electrochemical properties. The overall performance of the present crosslinked polymer network electrolyte containing solvated ionic liquid systems postulates the possibility of their practical implementation in the construction of safe and durable alternative electrolytes for high‐performance lithium ion batteries working at wide temperatures. [ABSTRACT FROM AUTHOR]

[Display omitted] The effect of the chemical component and microstructure, not to mention their facile modification, of the coating/wrapping carbon layer on the electrochemical performance of the Si/C composite anode in lithium ion batteries (LIBs) hasn't been actively explored although Si/C has been recognized as one of the most promising route for the high energy density LIBs. Herein we propose a novel nitrogen-plasma doping route to modify the top carbon film in an elaborately constructed layered Si/C composite anode. The electrochemical performance, e.g., the initial coulombic efficiency (CE), cycle stability and specific capacity of the composite anode is drastically improved by this plasma processing due to the increased kinetics of lithium ions. By means of the appropriate adjustment of the N doping ratio and N chemical configuration in the carbon layer through a N 2 /H 2 plasma processing, the lithium diffusion rate in the composite anode was memorably increased as the pseudocapacitance effects promoted. The optimized Si/C composite exhibits a high capacity of 1120.7 mA h g−1 and an initial CE of 80.8% at the current of 2 A g−1 after a long cycle of 1500, increasing by ~40% of specific capacity and ~29% of the initial CE. [ABSTRACT FROM AUTHOR]

SiOC as an alternative silicon-based material possesses great potential in lithium ion batteries due to its high reversible capacity, tunable chemical component and various synthetic route. However, large-scale production of SiOC powders grinded from SiOC bulks is restricted in commercial application because of the poor electrical conductivity. Herein, three dimensional (3D) lamellar SiOC@C/rGO composite is fabricated through hydrothermal reaction and electrostatic self-assembly process, in which SiOC powders encapsulated by amorphous carbon layers are homogeneously dispersed in graphene sheets. C free nanoclusters in SiOC, carbon layers on SiOC surface and graphene supporters in the composite establish the multidimensional interconnected conductive architecture and possess favorable interfacial adhesion. Therefore, SiOC@C/rGO exhibits high specific capacity (676 mAh g−1 at 200 mA g−1) and remarkable rate capability (306.4 mAh g−1 at 4000 mA g−1). The full cell assembled with this anode and LiFePO 4 cathode also demonstrates stable voltage platform and good performance for 200 cycles. The excellent performance of SiOC@C/rGO profits from the synergistic effect of robust construction, multidimensional conductive architecture and chemical. The proposed strategy can also be developed to prepare other materials with graphene layer to enhance their electrical conductivity for commercial application. [Display omitted] • SiOC@C/rGO was fabricated through electrostatic self-assembly process. • Electrostatic repulsion between SiOC@C and GO was eliminated using a surfactant. • 3D conductive architecture was constructed by C free in SiOC, C layer and graphene. • Evenly dispersed SiOC and increased oxygen-rich SiOC units improved the capacity. • SiOC@C/rGO exhibits good electrochemical performance in both half and full-cell. [ABSTRACT FROM AUTHOR]

The electrochemical performance of lithium ion batteries is closely related to the solid electrolyte interphase (SEI) film formed on anode surface. Despite the widespread commercialization of graphite anodes, SEI still suffers from unsatisfactory stability, leading to gradual loss of active lithium ions and capacity degradation of batteries. Here organic small molecular salts with unsaturated bonds and diverse anions are coated on graphite particles and work as substrates to form a modified SEI. The C C double bond-containing organic salts, sodium acrylate (SA), sodium vinylsulfonate (SVS) and vinyl sodium phosphate (VSP), possessing carboxylate, sulfonate and phosphate groups, respectively, are rationally selected and their effects on the SEI and electrochemical properties of graphite anodes are systematically investigated. SVS modified graphite generates a SEI film with high flexibility, good compactness and lithium ions conductivity owning to the in-situ polymerization of carbon double bonds and polarity of ionic sulfonate groups. Accordingly, the first coulombic efficiency, rate capability and cycle life of graphite anodes are improved in both half cell and LiNi 0 · 6 Co 0 · 2 Mn 0 · 2 O 2 -based full cell testing. [Display omitted] [ABSTRACT FROM AUTHOR]

The metal selenides/tellurides have attracted considerable concerns for high-capacity lithium ion batteries (LiBs) because of their high conductivity, low voltage polarization and high theoretical coulombic efficiency. However, poor cyclability is still a big challenge that impedes their practical applications. Herein, GeSe2/Carbon (GeSe2/C) composite was fabricated by solid-state reaction method and its lithium ion (Li+) storage performances were investigated using flexible polyacrylonitrile (PAN) gel polymer electrolyte as separator. Reversible capacity of the GeSe2/C|PAN|Li system was ~20% higher than that of the GeSe2/C|polypropylene (PP)|Li system. Upon NaCl-assisted ball milling process, SEM and TEM observations revealed that the size of GeSe2/C particles significantly decreased from 30 μm to 100–500 nm. The milled GeSe2/C displayed a high capacity of 623.6 mA h g−1 at 350th cycle, which was 90.7% of the 2nd discharge capacity value, and the reversible capacity showed a 1100% improvement by using PAN as separator compared to the conventional PP separator. This study might inspire manufacturing of high-performance LiBs for energy storage. [Display omitted] [ABSTRACT FROM AUTHOR]

Graphite nanosheets coated by LiF/SnO 2 composites are designed to obtain a lithium ion anode material with excellent performance. LiF nanoparticles play a significant role in improving the electrochemical performance by inhibiting electrolyte decomposition and providing excess Li sources during cycling. The obtained LiF@SnO 2 @C electrode shows an outstanding capacity of 951.9 mAhg−1 at 0.2 Ag-1 after 370 cycles and excellent long cycling performance of 650.0 mAhg−1 at 1.0 Ag-1 after 930 cycles. First-principles calculations demonstrate that F-doped SnO 2 (−2211.8 eV) has a lower free energy compared to SnO 2 (−1937.4 eV), resulting in a robust composite architecture that gives rise to high cycling stability. [ABSTRACT FROM AUTHOR]

Improving the high‐rate performance of spinel lithium titanate (Li4Ti5O12, LTO) is one of the critical requirements to promote its practical application in Li‐ion batteries (LIBs). Herein, the possible Li+ ion diffusion routes in LTO are theoretically analyzed and compared by computational investigation. The calculations show that the most feasible diffusion path for Li+ ions is along the [110] direction indicated by the lowest energy barrier. Inspired by this prediction, ultrathin [110]‐confined LTO nanoflakes are rationally prepared through a function‐led targeted synthesis. The [110] orientation of the material sufficiently provides preferable transport channels which can promote the anisotropic diffusion of lithium ions within LTO nanoflakes. Furthermore, the ultrathin 2D nanostructure effectively shortens the diffusion length along the [110] direction, facilitating ion transport across the nanoflakes and thus improving the diffusion kinetics. Owing to these unique features, the LIB composed of optimized [110]‐confined LTO exhibits remarkable high rate capability and long‐term cycling stability, with a capacity of 146 mAh g‐1 at an ultrahigh rate of 100 C and a capacity retention of 88% even after 1500 cycles at 50 C. The as‐prepared [110]‐confined LTO nanoflakes have promising applications and show commercial viability for high‐power facilities. [ABSTRACT FROM AUTHOR]

A novel Sn(OH)4/mesocarbon microbeads (MCMB) anode material has been successfully prepared by skillfully encapsulating the Sn(OH)4 nanoparticles into the micropores of MCMB via a simple vapor deposition approach. The electrochemical results demonstrate that the Sn(OH)4/MCMB anode exhibits a high reversible capacity of 904 mAh g−1 after 500 cycles at a current density of 100 mA g−1, which is far higher than that of the SnO2/MCMB (501 mAh g−1) and Sn/MCMB (364 mAh g−1). Such transcendence can be attributed to the ultrasmall sizes of Sn(OH)4 nanoparticles and rapid lithium ions transport channels provided by micropores on the surface of MCMB. More importantly, the encapsulated Sn(OH)4 particles inside the micropores decrease the exposure to the electrolyte to ensure the formation of stable solid electrolyte interphase films as well as accommodating electrode expansion during charge–discharge, which is beneficial to achieve a stable cycling performance. Therefore, the unique nanostructures of Sn(OH)4/MCMB ensure it becomes a novel promising anode material for the high‐performance lithium ion batteries. [ABSTRACT FROM AUTHOR]

CaMnO 3 , a perovskite-type material, has been introduced as a novel anode material for lithium ion batteries, and its electrochemical performance at different temperatures is systematically investigated. The as-prepared CaMnO 3 material exhibits a high specific capacity, favorable rate performance and excellent cycling stability. The CaMnO 3 anode could deliver a high specific capacity of 102.5 mAh g-1 after 500 cycles at a current rate of 0.1 A g-1. Lithium ion batteries are attracting ever increasing attention due to their advantages of high energy/ power density, environmental friendly, lifetime and low cost. As a star in the field of materials and energy, perovskites have received extensive attention due to their attracting physical and chemical properties. Herein, CaMnO 3 , one material from the perovskite family is introduced as a novel anode material for lithium ion batteries, and its electrochemical performance at different temperatures is systematically investigated. CaMnO 3 has been synthesized using a liquid phase synthesis method followed by high temperature calcination. The as-obtained CaMnO 3 exhibits an initial high discharge capacity of 708.4 mAh g−1, superior rate capability and stable cycling performance at room temperature, the specific capacity is 102.5 mAh g−1 after 500 cycles at a current density of 0.1 A g−1. Additionally, at an extreme temperature of 0 °C, the discapacity can reach 138.2 mAh g−1 at a current density of 0.05 A g−1. At high temperature of 50 °C, the reversible discharge capacity is up to 216.5 mAh g−1under the same condition. It is believed that this contribution may lay the foundation for the application of perovskites in other rechargeable batteries and energy storage devices. [ABSTRACT FROM AUTHOR]

Hollow multi-shelled spherical Co 3 O 4 /CNTs composite was prepared by a facile MOF-assisted strategy by introducing carbon nanotubes (CNTs) directly into the precursor. The hierarchical porous structure of the obtained multi-shelled Co 3 O 4 nanospheres can effectively alleviate volume change and facilitate the infiltration of electrolyte into the interior. The interconnected CNTs can reduce the electrochemical polarization by improving the conductivity of the body material. As an anode for lithium ion batteries, the as-synthesized Co 3 O 4 /CNTs composite exhibits superior lithium ion storage performance. A high reversible specific capacity of 653.1 mAh g−1 was obtained after 500 cycles at 1000 mA g−1, suggesting a significant inspiration for fabricating application for advanced electrochemical devices. • Hollow multi-shelled spherical Co 3 O 4 /CNTs composite was prepared by a facile MOF-assisted strategy. • The hierarchical porous structure can alleviate volume change and facilitate the infiltration of electrolyte. • A high reversible specific capacity of 653.1 mAh g−1 was obtained after 500 cycles at 1000 mA g−1. [ABSTRACT FROM AUTHOR]

Morphological control is a fundamental challenge of nanomaterial development. Commonly, hierarchical nanostructures cannot be induced by a single driving force, but obtained through balancing multiple driving forces. Here, a feasible strategy is reported based on the synergistic effect of proton and acid anion, leading to the morphological variation of vanadium oxide from nanowire, bundle, to hierarchical nanoflower (HNF). Protons can only induce the formation of nanowire through reducing the pH value ≤ 2. However, acid anions with strong coordination ability, e.g., phosphate radicals, can also participate in morphological regulation at high concentration. Through coordinating with exposed vanadium ions, the enrichment of phosphate radicals at ledge and kink changes the growth directions, giving rise to the advanced structures of bundle and HNF. The lithium ion batteries using HNF as a cathode achieve a 30% improved initial discharge specific capacity of 436.23 mAh g−1 at a current density of 0.1 A g−1, reaching the theoretical maximum value of vanadium oxide based on insertion/desertion of three lithium ions, in addition to strong cyclic stability at 1 A g−1. [ABSTRACT FROM AUTHOR]

Poor electrical conductivity and large volume changes are two disadvantages of metal selenides. In this work, MnSe nanoparticles encapsulated into N-carbon fibers are designed and prepared using electrospinning and calcination methods. When calcined at 700 °C, the composite has a high reversible capacity of 684 mAh g−1 after 100 cycles at 0.1 A g−1, owing to the improved conductivity and protection provided by carbon fibers. Furthermore, the in situ electrochemical impedance measurements reveal the process kinetics of the composites. This work will provide the basis for the further development of the application of metal selenides in the field of flexible electrodes. [ABSTRACT FROM AUTHOR]

Silicon monoxide (SiO x , 0 < x < 2) is considered to be one of the most promising anode materials, due to its higher theoretical specific capacity relative to graphite and smaller volume expansion rate relative to silicon materials. However, SiO x anode material still has its own disadvantages such as poor conductivity. In view of this situation, the SiO x /Ag/C composite material was synthesized with self-selective electroless deposition and carbon-coated technology by using ball-milled SiO x. Through the synergistic effect of Ag nanoparticles and the carbon layer, the electronic conductivity and the lithium ion diffusion coefficient of the SiO x /Ag/C composite was improved and its volume expansion was inhibited. Thus the SiO x /Ag/C composite of layered structure holds an excellent cycling performance with the discharge specific capacity of 1102.7 mAh·g-1 after 150 cycles at current density of 0.5C (1C = 2.1 A g-1), which is 345.1 mAh·g-1 higher than the discharge capacity of SiO x /C, and the SiO x /Ag/C composite shows 403.2 mAh·g-1 higher capacity than that of as-ball-milled SiO x at 2 C by rate performance test. [ABSTRACT FROM AUTHOR]

In this work, α-Fe2O3 double-layer hollow spheres with carbon coating (DLHS@C) are synthesized by a general "penetration-heterogeneous nucleation" approach using carbonaceous sphere templates combined with subsequent annealing. This hierarchy hollow sphere structure with carbon coating rationally combines three advantage aspects: shorten transport length for lithium ions and charges, sufficient void space to buffer the volume expansion, and enhanced electric conductivity. When tested for lithium storage, α-Fe2O3 DLHS@C composite electrode exhibits a high initial discharge capacity of 1735 mAh g-1 and the reversible capacity of 823 mAh g-1 after 100 cycles at the current density of 100 mA g-1 in the voltage range of 0.01–2.5 V (vs. Li+/Li) and retains a capacity of 470 mAh g-1 even at a large current density of 500 mA g-1 after 500 cycles. The α-Fe2O3 DLHS@C electrode demonstrates excellent electrochemical properties with high capacity, good cycling stability, and excellent rate capability as potential anode material for lithium ion batteries. [ABSTRACT FROM AUTHOR]

Practical applications of high gravimetric and volumetric capacity anodes for next‐generation lithium‐ion batteries have attracted unprecedented attentions, but still faced challenges by their severe volume changes, rendering low Coulombic efficiency and fast capacity fading. Nano and void‐engineering strategies had been extensively applied to overcome the large volume fluctuations causing the continuous irreversible reactions upon cycling, but they showed intrinsic limit in fabrication of practical electrode condition. Achieving high electrode density is particularly paramount factor in terms of the commercial feasibility, which is mainly dominated by the true density and tapping density of active material. Herein, based on finite element method calculation, micron‐sized double passivation layered Si/C design is introduced with restrictive lithiation state, which can withstand the induced stress from Li insertion upon repeated cycling. Such design takes advantage in structural integrity during long‐term cycling even at high gravimetric capacity (1400 mAh g−1). In 1 Ah pouch‐type full‐cell evaluation with high mass loading and electrode density (≈3.75 mAh cm−2 and ≈1.65 g cm−3), it demonstrates superior cycle stability without rapid capacity drop during 800 cycles. [ABSTRACT FROM AUTHOR]

Olivine-type LiFePO4 cathode material was successfully synthesized by a simple method of thermal explosion (TE) using hexamethylenetetramine (C6H12N4) as fuel. The crystalline phase, morphology and particle size of powders were characterized by X-ray diffraction, scanning electron microscope, particle size analyzer and transmission electron microscope measurements. And the electrochemical properties were investigated by galvanostatic charge–discharge tests and electrochemical impedance spectroscopy. The results indicated that the samples synthesized by TE showed an olivine crystal structure with space group Pnmb. In addition, both structure and particle size could be adjusted by the amount of C6H12N4 and the heat treatment temperature in the TE. When the amount of C6H12N4 was 30 wt%, the heat treatment temperature was 800 °C and the particle-size distribution fell in a range of 300–400 nm. Electrochemical tests indicated that the LiFePO4 sample synthesized in such conditions, without additional carbon coating and cation doping, shows a discharge capacity of 110.4 mAh g−1 and an excellent capacity retention rate of 87% after 50 cycles at 1 C. [ABSTRACT FROM AUTHOR]

Novel structured porous hollow six-branched star-like MnO was synthesized via a facile, surfactant-free hydrothermal decomposition, which was followed by high-temperature heat treatment. Compared with the nonporous hollow six-branched star-like MnO 2 , the porous hollow six-branched star-like MnO realized substantially higher electrochemical performance (844.8 mAh g−1 at 0.5 A g−1 after 200 cycles and 769.7, 741.7, 728.9, 713.2, and 704.4 mAh g−1 at 0.1, 0.3, 0.5, 1, and 1.5 A g−1, respectively, for porous star-like MnO, compared with 338.4 mAh g−1 and 476.7, 392.4, 357, 303.4, and 269.9, respectively, under the same testing conditions for nonporous star-like MnO 2). The superior performance of the porous hollow six-branched star-like MnO is attributed to its enhanced electrode kinetics, which are due to an enlarged active contact area and shortened electron and Li+ conduction paths. [ABSTRACT FROM AUTHOR]

Owing to the special structural characteristics, oxide derivatives of Prussian blue (PB)-based hollow structures are widely used in electrochemical energy storage and conversion. Here, Fe3O4 particles have been synthesized by one-step thermal decomposition of PB. The cube-sized iron-based PB and structural stability of thermal decomposition products at different amount of polyvinyl pyrrolidone (PVP) were well investigated. In the derivatived architecature, the hollow Fe3O4 nanocubes provide high-efficiency lithium ion transporation and the diffusion of electrolyte, enabling better electrochemical performance. The as-obtained Fe3O4 nanocubes show a remarkable rate capability (462 mAh g − 1 at 1.0 A/g) and outstanding specific capacity (803 mAh g − 1 at 0.1 A/g, 97.5% capacity retention over 140 cycles), which have a potential application as anode materials for lithium ion batteries due to the facile preparation method and high electrochemical performance. The hollow Fe3O4 nanocubes prepared by one-step thermal decomposition of PB provide high-efficiency lithium ions transporation and diffusion of electrolyte, enabling better electrochemical performance. The as-obtained Fe3O4 nanocubes show a remarkable rate capability (462 mAh g–1 at 1000 mA g–1) and outstanding specific capacity (803 mAh g–1 at 100 mA g–1, 97.5% capacity retention over 140 cycles). [ABSTRACT FROM AUTHOR]

Li4Ti5O12 (LTO) is one of the most promising high-power anodes for lithium ion batteries, but its large-current performance is still undermined due to relatively poor ion/electron transfer. In this work, we report a powerful hydrothermal method for fabrication of highly porous binder-free Li4Ti5O12 films, which show hierarchical structure composed of interconnected primary nanoparticles of 50-100 nm and secondary nanowalls. The lithium ion storage performance of designed Li4Ti5O12 films is thoroughly studied and demonstrated with excellent high-rate performance. The as-prepared Li4Ti5O12 films exhibit a high specific capacity of 146 mAh g-1 at the current density of 2 C. In view of good structural stability, a notable cycling stability is verified with a specific capacity of 130 mAh g-1 after 5000 cycles at 2 C. Our method provides a novel route for synthesis of other advanced anodes for application in the field of ultrafast energy storage. Highly porous binder-free Li4Ti5O12 films are synthesised via a hydrothermal method and exhibit a noticeable high-rate electrochemical performance as the anode of lithium ion batteries. [ABSTRACT FROM AUTHOR]

Summary: The high theoretical capacity of Si makes it a promising anode material for lithium ion batteries. However, the poor electrical conductivity and large volume expansion during lithiation/delithiation hinders its electrochemical performances. Herein, we report a γ irradiation treatment method to prepare P‐doped Si nanoparticles. The sample exhibits a capacity of 1698 mAh/g at 0.1 C rate after 100 cycles, which is about 3 times larger than that of undoped Si. The rate performance of γ irradiated P‐doped Si is also highly improved when compared to P‐doped Si without γ irradiation treatment. The enhanced performance can be attributed that γ irradiation can facilitate the phosphorus doping into Si lattice, which can enhance the electrical conductivity of Si. [ABSTRACT FROM AUTHOR]

Glasses are promising anode materials for Li‐ion batteries (LIBs) owing to their unique open network structures and the absence of grain boundaries. Upon discharging/charging, both the capacity and cycle life of the glass anodes can be affected through their structural evolutions. This review article highlights the recent research advances in improving and understanding the electrochemical performances of various types of glass anodes. Both the SnO‐ and GeO2‐based glass anodes suffer from the high initial capacity loss and short cycle life. The origin of the first‐cycle irreversible capacity loss is discussed primarily from the structural evolution with cycles, that is, forming metallic Sn/Ge in the glass matrix. Recently, significant breakthroughs have been achieved in enhancing cycling stability and capacity of the anode materials by means of the disorder‐order engineering with respect to the V2O5–TeO2 glass systems. In addition, the most recent advances in the applications of dual‐phase glass anodes in LiBs are reviewed. This article gives an overview of the applications of the glass anodes, as well as deals with the structural factors affecting their electrochemical performances. A deeper understanding of these factors will enable further steps toward improvement and application of the glass anodes for LIBs. [ABSTRACT FROM AUTHOR]

Summary: A high throughput mass production of separator is proposed using a well‐established unique in‐house process of roll‐to‐roll atmospheric atomic layer deposition. An ultra‐thin conformal layer of Al2O3 is deposited over the commercial Celgard (PE/PP/PE) using multi‐slit gas source head. Overall 10 nm increase is incurred in the thickness, while maintaining the porosity to ~48%. The entire process of fabrication was performed at very low temperature of 90°C. The high thermal stability of as‐modified separator is achieved at of 180°C. The separator was analyzed using X‐ray photoelectron spectrometer, electrochemical impedance spectra, and field emission scanning electron microscope. The as‐developed separator showed excellent wettability due to the surface medication in addition to robust flexibility, high conformity, and minimal thermal shrinkage. The Lithium cobalt oxide (LCO)/Graphite cells with atomic layer deposition (ALD) Celgard (Al2O3 deposited) separator delivered remarkable discharge capacity with 79.5% capacity retention after 100 cycles at 1 C as compared to the uncoated‐separator(Celgard separator), which yielded relatively less retention of ~70%. Moreover, the LCO/Graphite cells with the ALD‐Celgard separator delivered the discharge capacity of 140 mAh/g at elevated temperature (up to 80°C). [ABSTRACT FROM AUTHOR]

A porous carbon nanocomposite with embedded TiO 2 nanowires (NWs) was synthesized using a two-step synthetic method in which carbon matrix was obtained by carbonizing a vacuum dried gel. This unique structure in which TiO 2 nanowires uniformly distributed in and tightly bonded to the carbon matrix shortened the electron transport path and reduced the transmission resistance. Nanoporous structure ensured continuous transfer of Li+/Na+ and supplied a large specific surface area of 280.82 m2 g−1 to provide more active sites. Different from other existing works on TiO 2 @C anode materials with TiO 2 loading higher than 60 wt%, the obtained very small amount of TiO 2 (~12 wt%) improved the electrochemical and long-cycle performance of carbon substrate with TiO 2 NWs embedded significantly, due to uniformly distributed TiO 2 NWs throughout the carbon matrix. These TiO 2 @C composite anodes could deliver a specific capacity of 286 mA h g−1 at 0.3 C, 197 mA h g−1 at 0.15 C for lithium and sodium ion batteries, respectively. It maintained remarkably stable reversible capacities of 128 and 125 mA h g−1 for lithium and sodium ion batteries at 3 C during 2500 cycles, respectively. Smaller fluctuations and smoother curves demonstrated that sodium ion storage was more stable than lithium ion storage for the TiO 2 @C composite anode. In addition, the capacitive contributions of TiO 2 @C in both systems are quantified by kinetics analysis. [ABSTRACT FROM AUTHOR]

Carbon materials are frequently used to improve the cycle and rate performance of VS4 as anode material for lithium ion batteries. However, the interfacial interaction between VS4 and carbon has not been elucidated clearly. Various VS4@C composites are prepared and the interface between VS4 and porous carbon is investigated by X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and first‐principles calculations. The interfacial structure between VS4 and carbon and the mechanism of flower‐like VS4 growth on carbon substrate are revealed clearly. The results indicate that C−V bonds and C−O−V bonds are formed when oxygen functional groups are introduced into the porous carbon, and the C−V bonds and C−O−V bonds accelerate the electron transport and enhance structural stability of the VS4@C composite. Deriving from the unique structure and robust interfacial interaction, the electrochemical performances of VS4@C composite are much better than that of pure VS4. Moreover, through the study of lithium storage mechanism of VS4 anode, it is found that there is an irreversible amorphization change of the original VS4 in the first cycle, and that during the following electrochemical process, the main storage behavior of lithium ions derives from the insertion−extraction reactions in the amorphous VS4 with the reaction between V4+ and V3+. [ABSTRACT FROM AUTHOR]

Conversion‐type transition metal oxide MoO3 has attracted considerable interest as a promising anode material for lithium ion batteries (LIBs), but it suffers from the low electronic conductivity and the large volume changes upon lithiation/delithiation. To overcome these drawbacks, we herein report the full encapsulation of core‐shelled MoO3‐TiO2 into the carbon nanofibers (CNFs) via a facile coaxial electrospinning followed by a two‐step annealing process. TiO2 shells and MoO3 cores were coaxially integrated into the porous CNFs (denote the composite as TiO2/MoO3@CNFs). The two‐step annealing strategy (carbonization in Ar and then oxidization in air) allows the readily encapsulation of MoO3 into CNFs. When applied as anode materials for LIBs, the coaxial TiO2/MoO3@CNFs demonstrate superior lithium storage performance, delivering a high reversible capacity of 561 mAh/g after 300 cycles at 1000 mA/g with a much higher capacity retention of 70.8% than that of the MoO3@CNFs without TiO2 layers (only 42.3%). The results clearly demonstrate that the CNFs matrices and the TiO2 shells together efficiently enhance the electrode conductivity and buffer the volume changes of MoO3 upon cycling. [ABSTRACT FROM AUTHOR]

Hierarchical porous chromium niobium oxide (Cr 0.5 Nb 24.5 O 62) microspheres are prepared by a facile one-step solvothermal method and demonstrated with noticeable lithium ion storage performance with superior high-rate capability (199 mAh g−1 at 20C) and good cycling stability. • Construct hierarchical porous Cr 0.5 Nb 24.5 O 62 microspheres as anodes. • Hierarchical porous Cr 0.5 Nb 24.5 O 62 microspheres show high capacity. • Hierarchical porous structure is favorable for fast ion/electron transfer. Controllable fabrication of advanced electrode materials is critical for the development of lithium ion batteries (LIBs). Herein, for the first time, we report novel hierarchical porous chromium niobium oxide (Cr 0.5 Nb 24.5 O 62) microspheres prepared by a facile one-step solvothermal method. The as-prepared Cr 0.5 Nb 24.5 O 62 microspheres present 3D hierarchical porous structure consisting of cross-linked nanoparticles, high electronic conductivity and large specific surface area. Accordingly, the Cr 0.5 Nb 24.5 O 62 microspheres show noticeable lithium ion storage performance with superior high-rate capability (199 mAh g−1 at 20C) and good cycling stability with a capacity retention of 95% over 1000 cycles, much better than the bulk Cr 0.5 Nb 24.5 O 62 and TiNb 24 O 62 counterparts. Our work demonstrates a new high-rate electrode material for high-power energy storage. [ABSTRACT FROM AUTHOR]

Nd:BiVO 4 nanocrystals were synthesized by an effective and simple approach. Nd was incorporated into BiVO 4 host to enhance electronic conductivity and lithium-ion diffusion kinetics, thus promoting the electrochemical performance. When employed as anode materials in lithium-ion batteries, a good cycling stability and high capacity of ~611 mAh g−1 at 100 mA g−1 were delivered. The work can be extensively employed for fabricating other electrode materials and promoting the electrochemical performance in energy storage correlative domains. [ABSTRACT FROM AUTHOR]

Summary: The serious capacity decay caused by structural amorphization is still a major issue for polyanion‐type lithium manganese silicates (Li2MnSiO4) as cathode material for lithium ion batteries. In this work, a new strategy for alleviating the structural instability via the introduction of excess lithium into the host crystal lattice is provided. A comprehensive study demonstrates that the required energy for the extraction/insertion of lithium ions into host crystal lattice was decreased as a result of changed local environment of cations in the compound after the excess lithium occupancy in lattice. Importantly, it was found that Li‐rich samples deliver higher reversible capacity and increased average potential than pristine sample, indicating the improved energy density of polyanion‐type Li2 + 2xMn1 − xSiO4/C. Additionally, the structure of Li2.2 sample was kept intact, while the Li2.0 sample was transformed to amorphous state at 200 mA h g−1 during the initial charging process by controlling the charge cut‐off potential. As expected, the introduction of a certain amount of excess lithium into Li2MnSiO4 is explored as a route to achieving increased capacity with more movable lithium, while maintaining its structural stability and cyclic stability. [ABSTRACT FROM AUTHOR]

Sodium molybdate (Na−Mo−O) wrapped by graphene oxide (GO) composites have been prepared via a simple in‐situ precipitation method at room temperature. The composites are mainly constructed with one dimension (1D) ultra‐long sodium molybdate nanorods, which are wrapped by the flexible GO. The introduction of GO is expected to not merely provide more active sites for lithium‐ions storage, but also improve the charge transfer rate of the electrode. The testing electrochemical performances corroborated the standpoint: The Na−Mo−O/GO composites delivers specific capacities of 718 mAh g−1 after 100 cycles at 100 mA g−1, and 570 mAh g−1 after 500 cycles at a high rate of 500 mA g−1; for comparison, the bare Na−Mo−O nanorod shows a severe capacity decay, which deliver only 332 mAh g−1 after 100 cycles at 100 mA g−1. In view of the cost‐efficient and less time‐consuming in synthesis, and one‐step preparation without further treatment, these Na−Mo−O nanorods/GO composites present potential and prospective anodes for LIBs. [ABSTRACT FROM AUTHOR]

Though lithium ion batteries are popular in many fields, high performance electrode materials with reasonable structure are desired. Herein, Sn/nitrogen-doped graphene (NGN) was fabricated with the help of 7,7,8,8-tetracyanoquinodimethane anion (TCNQ∙-). TCNQ∙- was used to anchor Sn4+ into the graphene layer with the electrostatic interaction, which improves the distribution of Sn nanoparticles. Meanwhile, TCNQ∙- acts as a nitrogen source to construct N doped graphene, enhancing the electron conductivity of the composite. Benefiting from the strong structure and good ion/electron conductivity, the Sn/NGN composite achieved excellent electrochemical battery performance. At high rates of 1 and 2 A g−1, capacities of 433 and 353 mA h g−1 were acquired, respectively. Moreover, the Sn/NGN composite outputted a high capacity of 584 mA h g−1 at the end of 1000 cycles at 1 A g−1. • Sn/N-doped graphene (NGN) was obtained by a simple liquid method with the help of 7,7,8,8-tetracyanoquinodimethane (TCNQ). • Sn/NGN composite exhibits good rate capability and long cycle performance at 1 A g−1. • TCNQ∙- anions are avorable for anchoring Sn4+ on graphene oxide and act as a nitrogen source for N doping on graphene. [ABSTRACT FROM AUTHOR]

A novel hierarchical porous carbon-Fe 3 O 4 composite are fabricated as an anode material for Li-ion batteries. In our design, hollow carbon spheres, HCSs for short, with elasticity are encapsulated in Fe 3 O 4 @C nanodisc. During the lithiation process, the out carbon shell confines particle-level outward expansion and ensure the structural integrity and stability. Meanwhile the embedded HCSs can provide void space to tolerate the volumetric expansion inwards. Subsequently, during the delithiation process, the HCSs could push the pulverized particles to contact together, ensuring good electrical contact between the pulverized particles and the outer carbon shell. The unique inward lithium-ion breathing design is helpful to maintain the structural integrity and ensure good inter- and intra-particle electrical contact. Therefore, the HCSs@Fe 3 O 4 @C nanodisc delivers an excellent high-rate cycling performance, giving a specific capacity of 595 mAh g−1 after 800 cycles at a current density of 1A g−1, and at a higher rate of 5 A g−1, having a specific capacity of 390 mAh g−1 after 1000 cycles. This work provides a new strategy for the design of high-volume expansion anodes in Li-ion batteries. Image 1 • Hollow carbon spheres (HCSs) encapsulated in Fe 3 O 4 @C nanodisc are introduced. • A structural model of inward lithium-ion breathing is established. • HCSs provide space to buffer the inward expansion of electrode materials. • Elastic HCSs make the pulverized intra-particles good electrical contact. • Excellent high-rate capacity and cycling performance. [ABSTRACT FROM AUTHOR]

Mesoporous titanias (MTs) with controllable structural properties were successfully synthesized following a sol-gel method for improved electrochemical characteristics for lithium-ion batteries (LIBs). Under the experimental conditions studied herein, by carefully considering the synthesis conditions including template type, amount of nitric acid and template, the BET surface area, pore volume and pore size of the resulting MTs could be adjusted in wide ranges of 83 m2g-1 to 170 m2g-1, 0.10 cm3g-1 to 0.46 cm3g-1 and 3.1 nm–12.6 nm, respectively. When used as anode for LIBs, the intrinsic mesoporosity of MTs enabled the large contact interface with electrolyte, thus the substantially reduced resistance of lithium ions, afforded the MTs to possess good cycling performance and rate capability. Herein, a stable specific capacity of 131.2 mA h g−1 even after 1000 cycles at 1C rate was obtained. The capacity fade rate per cycle was only 0.016%, showing an excellent potential for application in high-power LIBs. Image 1 • Successful control of the structural properties of TiO 2 by sol-gel method. • Interconnected pores and large specific area facilitate Li+ mobility. • Exceptional long-term cycling and rate capability were demonstrated. [ABSTRACT FROM AUTHOR]

In this reported study, Li 3 NbO 4 -based, Li-excess cathode materials xLi 3 NbO 4 •(1-x)LiMnO 2 (0.2 ≤ x ≤ 0.5) were synthesized using a solid state reaction method. XRD results showed that the fabricated powders with x = 0.3–0.5 could be indexed to a typical rock-salt structure (Fm-3m space group). Rietveld refinements showed that the lattice parameters increased with the increase in Nb5+ content. SEM and TEM images of the product showed that the elements Nb, Mn and O were evenly distributed in the samples, which further confirmed the cubic rock-salt structure of the product. Electrochemical tests of the samples showed that the sample with x = 0.4 exhibited the best electrochemical performance (232 mAh/g in the first cycle and more than 175 mAh/g in 50 cycles, as well as relatively high discharge capacity at high discharge current density). The redox mechanism analysis of the experimental results indicated that there were two stages in charge process: one was the Mn3+/4+ oxidation reaction below 4.3 V, and the other was related to the oxidation of O2− to O− or the release of O 2 , which improved the reversible capacity of the material. The structural evolution analysis of the samples showed that a spinel phase structure was present during the cycling process and the shift in the XRD peaks indicated that the sample with x = 0.4 exhibited the best structural stability. The electrochemical impedance spectroscopy analysis showed that the sample with x = 0.4 had the smallest R ct. The results for the kinetics of lithium ion diffusion indicated that the sample with x = 0.4 had largest D Li +, which was consistent with the best electrochemical performance for this material, especially the rate capability. • The good crystallized Li 3 NbO 4 -based materials are synthesized by a solid state reaction method. • The material 0.4Li 3 NbO 4.•0.6LiMnO 2 shows excellent electrochemical performance. • The highest Li+ diffusion coefficient and structure stability are response for the best performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Expandable single crystal organic precursors to form carbon composites for Li battery. • Carbon nanosheets with nickel-N-doping have high performances in cycle and rate. • Microporous-mesoporous structure formed by metal and N doping enhances Li+ adsorption. • DFT is used to study the adsorption and diffusion of Li+ in the metal-N-doping carbon. Organic-based and metal-organic-based matters are used as electrode materials or precursors for lithium ion batteries because of their high chemical stability and flexible molecular adjustability. Nevertheless, the unobvious electrochemical performance and unclear structure hinder the study of the lithium ions storage mechanism of them. In this paper, we design a well-defined single-crystal structure of organic crystal precursor (CN-Ni/Mn) and derived porous carbon nanosheets with metal-nitrogen-doping (CN-Ni/Mn-800) as electrode materials to construct independent high-performance lithium ion batteries. The study shows that a large number of interconnected micropore mesoporous structures obtained by the transformation of macropores in the materials improve the lithium storage capacity. Density functional theory (DFT) calculations show that the lithium ions adsorption energy and diffusion ability of CN-Ni/Mn-800 are higher than those of N-doped carbon-based materials (CN-800). CN-Ni-800 has the best performance among the anode materials of the half battery. It can deliver stable long-term cycling performance over 1000 charge-discharge cycles at 500 mA g−1. This is a new strategy that designed precursors with a single-crystal structure to derive carbon-based materials for developing high-performance batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • The addition of graphite plays an important role in improving electronic conductivity by forming conductive framework. • Excellent lithium ions diffusion has been achieved due to the generation of Li 3 N solid electrolyte stemming from melamine involvement. • Micron-SiO x anode synchronously modified by graphite and melamine (SiO x /G@M) exhibits significantly alleviated volume change. Silicon-based anodes with high theoretical capacity suffer from huge volume expansion and poor electronic conductivity. Herein, micron-SiO x anode synchronously modified by graphite and melamine (SiO x /G@M) with durable and superior electrochemical performance has been proposed through ball-milling and subsequent hydrothermal process. The good compatibility of melamine with SiO x prompts the generation of a uniform melamine coating on the surface of SiO x particles. Benefiting from the unique structural features, the as-prepared SiO x /G@M demonstrate higher initial Coulombic efficiency (ICE) and better electrochemical performance than SiO x /G. Specifically, a high reversible capacity of 990.4 mA h g−1 can be achieved at 100 mA g−1 after 200 cycles. And the capacity loss per cycle is only 0.016 % even at a high current density of 500 mA g−1 during 2000 cycles. The outstanding lithium-storage performance can be attributed to the significant role of graphite and melamine coating on facilitating rapid transport of both electrons and lithium ions, and plays a buffer role in large volume changes of Si-based anodes as well. [ABSTRACT FROM AUTHOR]

In this study, oxygen vacancies are successfully introduced into Li 2 MnO 3 by low-temperature reduction. Electron paramagnetic resonance is used to detect oxygen vacancy and the results state clearly that oxygen vacancies indeed exist in the reduced samples, and R-LMO-40 shows the highest content. The relationships between oxygen vacancies content and the electrochemical performance of Li 2 MnO 3 as cathodes for lithium ion batteries are also investigated. The oxygen-deficient samples show much better electrochemical performance compared to the pristine Li 2 MnO 3 , especially R-LMO-40 with an optimized content of oxygen vacancies. At the rates of 0.5 C, 1 C, 2 C and 5 C, R-LMO-40 delivers discharge capacities of 143.1, 134.0, 126.1 and 90.9 mAh g−1, respectively. After cycling for 50 cycles, there is nearly no capacity decay. These better electrochemical performances are believed to be related to the characteristics of the oxygen vacancies. Electrochemical impedance spectroscopy analysis clearly indicates that oxygen vacancies can suppress the charge transfer resistance and increase lithium ions diffusion capability. These findings reveal that oxygen vacancies can be utilized to enhance the electrochemical performances of Li-rich oxide cathode materials. Unlabelled Image • A series of the oxygen-deficient Li 2 MnO 3 are prepared by low temperature reduction process. • The contents of oxygen vacancies in the Li 2 MnO 3 are controlled by adjusting the amounts of reducing agents. • The effects of oxygen vacancies contents on the electrochemical performance of Li 2 MnO 3 are investigated. • Oxygen vacancies can significantly improve the cycling performance and rate capability. [ABSTRACT FROM AUTHOR]

Olivine-type LiFe x Mn 1- x PO 4 /C cathode materials are of great interest for lithium-ion batteries because of their higher lithium ion intercalation potential compared with that of LiFePO 4. Two types of LiFe 0.5 Mn 0.5 PO 4 /C nanorods with different sizes and crystal structures were synthesized through a facile glycol-based solvothermal process with different precursor feeding sequences. The microstructural investigation revealed that the size and structure of the LiFe 0.5 Mn 0.5 PO 4 nanorods can be tuned by nucleation and crystal growth rates of the intermediate precipitates, which can be controlled by precursor feeding sequence. The LiFe 0.5 Mn 0.5 PO 4 nanorods obtained through the first feeding sequence (a solution of transition metal salts was added dropwise into the solution mixture of LiOH and H 3 PO 4) exhibited less exposure of the (010) crystal faces and had bigger sizes compared with those of the LiFe 0.5 Mn 0.5 PO 4 nanorods obtained through the second feeding sequence (a LiOH solution was added dropwise into the solution mixture of H 3 PO 4 and transition metal salts). Electrochemical investigations indicated that the LiFe 0.5 Mn 0.5 PO 4 nanorods obtained through the second feeding sequence showed substantially improved electrochemical performance, in which the discharge capacities reached 157 and 119 mAh g−1 at 0.2 and 5 C, respectively. Furthermore, a capacity retention of 89% was obtained after 500 cycles at 1 C, demonstrating excellent cyclic stability. Image 1 • LiFe 0.5 Mn 0.5 PO 4 /C nanorods with large exposed (010) faces have been synthesized. • Fast precipitation causes formation of LiFe 0.5 Mn 0.5 PO 4 nanorods with fine sizes. • They show a high cyclic capacity, high stability and high intercalation potential. • Reversible capacity reaches 157 and 119 mAh g−1 at 0.2 and 5 C, respectively. [ABSTRACT FROM AUTHOR]

For the sake of seeking appropriate electrodes for Lithium ion battery which can be further extended for mass production. In this research, ball milling procedure has been utilized to synthesize V 2 O 5 /graphite electrode. The ratio of each phase in the composite can be easily manipulated. Meanwhile, SEM images demonstrated that homogeneous microstructure has been achieved with these different compositions. Specifically speaking, an optimal performance utilized as cathode material for lithium ion battery had been realized with 7.5V 2 O 5 /graphite, which maintains a specific capacity of 136 mAh g−1 after 150 cycles under the current density of 50 mAh g−1. Moreover, a relative high specific capacity of 113.3 mAh g−1 (at the current density of 1A g−1) can be retained after 300 cycles. In addition to enhanced cycling stability, the improved rate capability had also been achieved in this composition. Further investigation of CV results revealed that a capacitive behavior contributed by the introduction of graphite was responsible for this enhancement. Here designated composite exhibits great potential in electrochemical field. • V 2 O 5 /graphite composites were conventionally synthesized by ball milling. • The electrochemical performance was systemically investigated. • The enhanced capacitive behavior was responsible for this improved cycling stability. [ABSTRACT FROM AUTHOR]

A novel sphere-like SnO 2 /TiO 2 composite is synthesized via spray-drying followed by calcination as confirmed by X-ray diffraction and field emission-scanning electron microscopy analyses; the SnO 2 /TiO 2 composite is composed of the tetragonal cassiterite-like SnO 2 nanoparticles and anatase-like TiO 2 nanospheres. The characterization results show that the optimal stoichiometric ratio of SnO 2 /TiO 2 is approximately 3:1 when the composite serves as the anode for lithium ion batteries, in which the composite electrode not only delivers a high initial discharge specific capacity of 1476 mAh g−1 and retains 483 mAh g−1 after 40 cycles at 500 mA g−1 but also presents a low transfer resistance of approximately 56.33 Ω, a high Warburg coefficient of up to 85.82 Ω cm2 s−0.5, and a high lithium ion diffusion coefficient of approximately 6.934 E-15 cm2 s−1 at ambient temperature. These excellent electrochemical properties suggest that the SnO 2 /TiO 2 composite electrode may be a promising anode material for lithium ion batteries. [ABSTRACT FROM AUTHOR]

An intrinsic knowledge gap between current understandings obtained experimentally and the underlying working or degradation mechanisms of rechargeable lithium batteries still remains, giving direct rise to application challenges, e.g., safety issues, predicaments in identifying performance-aging factors and dilemmas in guiding further research directions. Against this background, non-destructive and three-dimensional (synchrotron) X-ray tomography that guarantees a direct visual access to inner electrodes has been employed herein to: in-situ record the evolution of internal short circuits; characterize the behaviors of widely employed separators; investigate the morphological evolution of Li electrodes under different cycling conditions; and study the degradation mechanisms of Li/carbon cells. By incorporating the currently presented results with the previously published studies on those topics, a complete picture of the degradation mechanism of rechargeable lithium batteries has been painted. This advancement of mechanistic understanding supplies the missing pieces of information to bridge fundamental R&D research activities and practical applications. [ABSTRACT FROM AUTHOR]

Abstract A series of cross-linked network solid polymer electrolytes based on dual end-functionalized polydimethylsiloxane bearing reactive thiol terminal groups with poly(ethylene glycol) diglycidyl ether and pentaerythritol tetrakis(3-mercaptopropionate) have been synthesized and characterized. The obtained results can be briefed as: ionic conductivity in the range of 1.5 × 10−6 S cm−1 at room temperature to 1.6 × 10−4 S cm−1 at 90 °C, lithium ion transference number ranged from 0.15 to 0.20, electrochemical window up to 5.3 V (vs. Li+/Li), thermal resistance (T d5 ca. 254.5 °C), and tensile strength (ca. 1.6 MPa at max.). The interplay taking place between structure and physico-electrochemical properties of in these systems based on merits of poly(ethylene glycol) moieties as high solvation matrix for Li+ ions flexible along with smooth solid support from polydimethylsiloxane allow the tailoring of the design of polymer electrolytes for future all-solid-state lithium batteries. Graphical abstract Image 1 Highlights • Network solid polymer electrolytes based on polydimethylsiloxane were fabricated. • Polydimethylsiloxane usage enhanced ionic conductivity of the electrolytes. • Mechanical and thermal properties were improved by the network structures. • The solid electrolytes showed favorable electrochemical properties for batteries. [ABSTRACT FROM AUTHOR]

Abstract The description of the transport mechanisms in operating Li ion battery cells is of key importance for a correct evaluation of their performance and for their optimization. In this work, we revise the Fickian approach for the description of the lithium transport in intercalation-type active materials. We adopt the Maxwell-Cattaneo-Vernotte (MCV) theory to capture the impact of lithium transport inertia on the electrochemical response of graphitic materials, taken here as an application example. We formalize this theory by means of an analytical mathematical expression which allows extracting the values of the lithium diffusion coefficient D MCV and the inertia characteristic time τ from potentiostatic intermittent titration technique (PITT) experiments. The implications of adopting the MCV theory in single particle models to calculate transient current response during the graphite lithiation are discussed (i) on the basis of the fitting of the calculations with in house PITT results and, (ii) by comparing the estimated diffusion coefficients with the ones resulting from the fitting using the classical Fickian approach. Highlights • Context of power LIB applications requiring high C-rate for short times. • Using Maxwell-Cattaneo-Vernotte theory capturing lithium transport inertia. • Method to extract theory parameters from PITT experiments. • Single particle model showing importance of considering lithium diffusion inertia. [ABSTRACT FROM AUTHOR]

Abstract Li 1.147 K 0.026 Mn 0.582 Ni 0.25 O 2 (LKMNO) sample is successfully prepared by doping K+ ions into Li slab without changing the original structure of Li 1.167 Mn 0.575 Ni 0.25 O 2 (LMNO). LKMNO sample delivers the capacities of 160.2 and 135.1 mAh g−1 at 1 and 5 C rates, respectively, but LMNO sample only delivers 135.1 and 0 mAh g−1. After 100 cycles at 1 C rate, LMNO and LKMNO samples respectively remain 67.4% and 93.0% of their initial capacities. The effects of K+ doping on the relationship between the charging-discharging process and phase change are detailed studied by the incremental capacity curves (d Q/ d V) at the various cycles. K+ doping in LKMNO sample plays an essential role in rate performance and cyclic performance, because it effectively hinders the formation of spinel structure and stabilizes the host layered structure. Considering the irreversible extraction of Li and O from the Li 2 MnO 3 region occurred beyond 4.6 V, after the charging/discharging are collected for 1–5 cycles at 2.5–4.9 V and 6–300 cycles at 2.5–4.6 V, LKMNO sample further reveals a remarkable improvement in cycling performance. In the full cell state (pouch cell), the discharge capacity of LKMNO is 194.6 and 115.4 mAh g−1 at 0.1 and 1 C rates, respectively, which are much higher than 175.5 and 79.7 mAh g−1 of LMNO sample. The capacity retention of LMNO and LKMNO samples is respective 48.8% and 74.9% of their initial capacity after 100 cycles. Graphical abstract Image 1 Highlights • Li 1.147 K 0.026 Mn 0.582 Ni 0.25 O 2 is successfully prepared by doping K+ into Li slab. • K+ doping results in Mn3+ state and is essential in rate and cyclic performance. • After 100 cycle LMNO and LKMNO remain 67.4% and 93.0% of their initial capacities. • K+ doping hinders the formation spinel structure and stabilizes the host structure. • In full cell LKMNO delivers two times capacity than LMNO at 1 C rate. [ABSTRACT FROM AUTHOR]