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Metal‐covalent organic frameworks (MCOF) as a bridge between covalent organic framework (COF) and metal organic framework (MOF) possess the characteristics of open metal sites, structure stability, crystallinity, tunability as well as porosity, but still in its infancy. In this work, a covalent organic framework DT‐COF with a keto‐enamine structure synthesized from the condensation of 3,3′‐dihydroxybiphenyl diamine (DHBD) and triformylphloroglucinol (TFP) was coordinated with Cu2+ by a simple post‐modification method to a obtain a copper‐coordinated metal‐covalent organic framework of Cu‐DT COF. The isomerization from a keto‐enamine structure of DT‐COF to a enol‐imine structure of Cu‐DT COF is induced due to the coordination interaction of Cu2+. The structure change of Cu‐DT COF induces the change of the electron distribution in the Cu‐DT COF, which greatly promotes the activation and deep Li‐storage behavior of the COF skeleton. As anode material for lithium‐ion batteries (LIBs), Cu‐DT COF exhibits greatly improved electrochemical performance, retaining the specific capacities of 760 mAh g−1 after 200 cycles and 505 mAh g−1 after 500 cycles at a current density of 0.5 A g−1. The preliminary lithium storage mechanism studies indicate that Cu2+ is also involved in the lithium storage process. A possible mechanism for Cu‐DT COF was proposed on the basis of FT‐IR, XPS, EPR characterization and electrochemical analysis. This work enlightens a novel strategy to improve the energy storage performance of COF and promotes the application of COF and MCOF in LIBs. [ABSTRACT FROM AUTHOR]

Lithium‐ion batteries (LIBs) have been widely used as a new energy storage system with high energy density and long cycle life. However, the solid electrolyte interface (SEI) formed on the surface of anode consumes excess active lithium during the initial cycle, resulting in an initial irreversible capacity loss (ICL) and reducing the overall electrochemical performance. To solve the critical issue, pre‐lithiation technology has been accepted as one of the most promising strategies. Due to the pre‐lithiated treatment provides additional active lithium to compensate for the ICL and effectively improves initial Coulombic efficiency (ICE), leading to raising the working voltage, increasing the Li+ concentration, as well as improving the energy density and cycle stability of LIBs. In this overview, the causes of ICL in LIBs are analyzed from different perspectives, and various pre‐lithiation strategies are systematically classified and summarized. Finally, some current problems and development prospects in this field are summarized, with prospects for realizing industrialized technologies. [ABSTRACT FROM AUTHOR]

Simultaneously achieving high energy density and high‐power density in energy storage systems is a crucial direction for developing next‐generation energy storage technologies. The high capacity and rapid kinetic performance of rechargeable proton batteries provide an ideal solution for overcoming energy limitation of capacitors and power constraints of traditional metal‐ion batteries. Research efforts primarily concentrated on electrode materials design, understanding the charge storage mechanisms, and exploring the failure mechanisms. While there has been relatively less emphasis on the modifications to electrolytes and electrode‐electrolyte interfaces to enhance overall performance. Summarizing and sorting relevant work is crucial in providing direction and suggestions for future research endeavors. Herein, to improve energy density, power density, and cycle stability of proton batteries, a series of recently published studies on electrolyte and electrode‐electrolyte interfaces are discussed and reviewed. Furthermore, challenges and future directions pertaining to the electrolytes of proton batteries have been identified, offering insights to facilitate the development of proton battery technology. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries (LIBs) are widely used in the mobile electronics, power, energy storage and other fields due to their excellent electrochemical performance, but their limited service life has resulted in a large number of spent LIBs being discarded. Due to the advantages of high recovery efficiency and mild reaction conditions, the combined pyro-hydrometallurgical process for recovering valuable metal elements from spent LIBs is emerging in line with the principles of green chemistry and has potential for large-scale industrial applications. Here we review current developments in the combined recovery process, aiming to figure out the challenges and future directions for the combined process. In detail, thermal pretreatment methods for collecting the cathode material from spent LIBs, the combined recovery process for treating the cathode material, and the subsequent separation and extraction process are summarized. Furthermore, the practical application of combined recycling schemes is demonstrated. Finally, the development and challenges of the combined process in recycling spent LIBs are revealed. Achieving pollution-free emissions and high-value utilization of spent LIB resources with low-cost treatment are future directions for the combined process. [ABSTRACT FROM AUTHOR]

A two-dimensional covalent organic framework (NTCDI-COF) with rich redox active sites, high stability and crystallinity was designed and prepared. As a cathode material for lithium-ion batteries (LIBs), NTCDI-COF exhibits excellent electrochemical performance with an outstanding discharge capacity of 210 mA h g−1 at 0.1 A g−1 and high capacity retention of 125 mA h g−1 after 1500 cycles at 2 A g−1. A two-step Li+ insertion/extraction mechanism is proposed based on the ex situ characterization and density functional theory calculation. The constructed NTCDI-COF//graphite full cells can realize a good electrochemical performance. [ABSTRACT FROM AUTHOR]

Highlights: By selecting 4-methylbiphenyl as an anion ligand and 2-methyltetrahydrofuran as a solvent, the as-prepared micro-sized SiO/C anode can achieve an initial Coulombic efficiency of ~100%. Molecular dynamics simulations demonstrate that the ideal prelithiation efficiency can be achieved by choosing appropriate anion ligand and solvent to regulate the solvation structure of Li+. The positive effect of pre-lithiation on cycle performance has been verified by using an in-situ electrochemical dilatometry and solid electrolyte interphase film. The solvation structure of Li+ in chemical prelithiation reagent plays a key role in improving the low initial Coulombic efficiency (ICE) and poor cycle performance of silicon-based materials. Nevertheless, the chemical prelithiation agent is difficult to dope active Li+ in silicon-based anodes because of their low working voltage and sluggish Li+ diffusion rate. By selecting the lithium–arene complex reagent with 4-methylbiphenyl as an anion ligand and 2-methyltetrahydrofuran as a solvent, the as-prepared micro-sized SiO/C anode can achieve an ICE of nearly 100%. Interestingly, the best prelithium efficiency does not correspond to the lowest redox half-potential (E1/2), and the prelithiation efficiency is determined by the specific influencing factors (E1/2, Li+ concentration, desolvation energy, and ion diffusion path). In addition, molecular dynamics simulations demonstrate that the ideal prelithiation efficiency can be achieved by choosing appropriate anion ligand and solvent to regulate the solvation structure of Li+. Furthermore, the positive effect of prelithiation on cycle performance has been verified by using an in-situ electrochemical dilatometry and solid electrolyte interphase film characterizations. [ABSTRACT FROM AUTHOR]

Siloxane‐based molecular material, by virtue of its unique chemical structure, thermal and electrochemical properties, has triggered tremendous research interest and sparked a revolution for energy storage in the past years. Siloxanes and their analogues are generally demonstrated to be more environmentally friendly, durable, and safer when employed to reconstruct the nano‐micro surface structure of electrodes, separators, and their interfaces with electrolytes. To better understand the recent and comprehensive achievement of siloxane‐based materials in energy storage, a systematic summary is necessary to provide important clues, aiming at achieving better electrochemical properties. In this Minireview, siloxane materials are presented comprehensively and systematically in terms of molecule design, functionality, and unique superiority for lithium‐ion batteries and supercapacitors. The challenges, perspectives, and future directions of siloxane‐based organosilicon materials are put forward for higher performance and wider application in electrochemical energy storage devices. [ABSTRACT FROM AUTHOR]

A novel hexaaminobenzene-based triangular topology covalent organic framework (HAB-COF) was first synthesized and studied as an anode material in the lithium-ion batteries. Benefiting from its conjugated structure and high-density C=N groups designed in the skeleton, the electrons transport and insertion/extraction of metal ions in HAB-COF got effectively promoted. Remarkably, upon a capacity-increasing and/or activation process, the HAB-COF organic electrode delivered high reversible capacities and excellent cycle life with a specific capacity of 1255 mAh g−1 at 1 A g−1 after 1100 cycles. Based on the analysis of cycled electrodes at different cycles, a stepwise-deepen thirty-electron lithiation mechanism of the covalent organic framework was speculated involving C=N bonds and steadily activated aromatic C=C groups. This work proves the potential of structure-designed COFs as electrode materials for high-capacity lithium-ion batteries, as well as deepens the fundamental understanding of storage mechanism. A novel covalent organic framework (HAB-COF) with high-density imine groups is synthesized and studied as an anode in the lithium-ion batteries. Upon a capacity-increasing process, the HAB-COF organic electrode delivers excellent cycle performance with a specific capacity of 1255 mAh g−1 at 1 A g−1 after 1100 cycles and even 1927 mAh g−1 at 0.1 A g−1. A thirty-electron lithiation mechanism involving C=N and aromatic C=C groups is proposed for the HAB-COF. [ABSTRACT FROM AUTHOR]

Residual lithium on the surface and the resulting side reactions for high‐energy‐density Ni‐rich layered oxide cathodes principally impede their industrial application and trigger safety concerns. Herein, the successful construction of LiBO2−B2O3 co‐modified single‐crystal LiNi0.6Co0.2Mn0.2O2 (SC‐NCM) as a lithium‐ion battery (LIB) cathode is reported. Boric acid reacts with the surface residual lithium species to form such uniform coating on the SC‐NCM particles, which presents advanced rate and cycling capabilities. As the cathode materials for LIBs, LiBO2−B2O3 co‐modified SC‐NCM delivers a 141.9 mAh g−1 discharge specific capacity at 5 C between 3.0 and 4.5 V versus Li+/Li with 61.4 % capacity retention after 500 cycles, superior to the 20.8 % retention for the pristine SC‐NCM cathode. Besides, the LiBO2‐B2O3 protective layer substantially inhibits the unexpected phase transformation, effectively alleviates the mechanical microcracks, and stabilizes the cathode‐electrolyte interface, even at an extended operational potential window. The proposed microstructure‐modified SC‐NCM cathode provides an affordable and feasible design strategy for Ni‐rich SC‐NCM cathodes towards stable electrochemical performance and prolonged service life at high potential. [ABSTRACT FROM AUTHOR]

Silicon-based materials, as the most promising candidates for high-performance lithium-ion batteries (LIBs), have been widely researched. However, the construction of stable electrode structure is still a challenge due to the enormous volume variation. Herein, we developed a three-dimensional (3D) binder network, polydopamine grafted cross-linked polyacrylamide (PDA-c-PAM), to build a durable anode for LIBs. The flexible PDA side chain in PDA-c-PAM offers the superior adhesion with constitutes of the electrode. And the 3D cross-linked PAM main chain endows PDA-c-PAM high stretchability to accommodate the volume variation of active material and maintain the structural integrity of electrode. As a binder for SiO/graphite (SiO/C), the fabricated SiO/C@PDA-c-PAM anode delivers an initial discharge capacity of 1350 mAh g−1 at 0.1 A g−1. At a high current density of 1 A g−1, it maintains 591 mAh g−1 after 300 cycles with a 94% capacity retention of initial capacity after activation. Coupled with commercial LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode, the full cell exhibits a high-energy density of 406 Wh kg−1 at 1 C as well as excellent stability. Thus, it is believed that designing 3D network binder is an effective approach to achieve superior cycle performance of SiO/C electrodes. We successfully synthesized a polydopamine grafted cross-linked polyacrylamide (PDA-c-PAM) polymer as binder for SiO/C anode to maintain the structural integrity and improve the cycling stability of electrode. The flexible PDA side chain in PDA-c-PAM offers the binder superior adhesion. And the 3D cross-linked PAM main chain endows the binder high stretchability. The fabricated SiO/C@PDA-c-PAM anode delivers a capacity of 591 mAh g−1 after 300 cycles at 1 A g−1. Thus, it is believed that designing 3D network binder is an effective approach to achieve superior cycle performance of SiO/C electrodes. [ABSTRACT FROM AUTHOR]

Most of the insertion anode materials are approaching their specific capacity limitations. TiNb24O62, combining the merits of high theoretical capacity, large working potential and excellent safety, is a promising candidate for lithium‐ion batteries (LIBs). However, its poor intrinsic conductivity and relatively sluggish reaction kinetics hinder its wide applications. Herein, we encapsulate the oxygen‐deficient TiNb24O62 microspheres by highly conductive N‐doped carbon nanolayer (DTNO@NC), where TiNb24O62 is purposely made to exhibit oxygen deficiency, by aerosol spray followed by co‐carbonization of the electronically coupled polydopamine (PDA) coating layer. The oxygen‐deficient engineering for TiNb24O62 improves the intrinsic conductivity and active sites, while the PDA derived N‐doped carbon coating layer not only stabilizes the interface between the electrode and electrolyte, but also further enhances the overall conductivity. As a result, the as‐fabricated DTNO@NC electrode delivers excellent Li+ ion storage capacity (270 mAh g−1 at 0.1 A g−1) and superior cycling lifespan (capacity retention of 90 % after 1000 cycles). This work demonstrates the effectiveness of integrating an oxygen‐deficient structure of intercalation‐type anode material with a carbon encapsulating nanolayer in enabling the overall energy storage performance. [ABSTRACT FROM AUTHOR]

Nickel‐rich cathode materials have been regarded as the most promising candidates for lithium‐ion batteries because of their superior specific capacity and cost‐effectiveness. However, the rapid capacity fade under high current density and serious side reactions during long‐term cycling hinder its wide application. In this study, piezoelectric BaTiO3 nanodots are employed as a functional coating layer on the LiNi0.6Co0.2Mn0.2O2 cathode material to balance the relationship between structure and performance. A three‐phase interface model is proposed including the LiNi0.6Co0.2Mn0.2O2 cathode material, uniform piezoelectric BaTiO3 nanodots, and the electrolyte. The coating layer plays a key role in the rapid diffusion of lithium‐ions as well as stabilizing the bulk structure of the cathode materials. Furthermore, the possible by‐products generated during the electrochemical cycling that can be alleviated by the modification of BaTiO3 are detected by using differential electrochemical mass spectrometry. As expected, our strategy efficiently improves the structural stability and holds a high‐rate performance. [ABSTRACT FROM AUTHOR]

Organic lithium ion batteries (LIBs) are considered as one of the next‐generation green electrochemical energy storage (EES) devices. However, obtaining both high capacity and long‐term cyclability is still the bottleneck of organic electrode materials for LIBs because of weak structural and chemical stability and low conductivity. Covalent organic frameworks (COFs) show potential to overcome these problems owing to its good stability and high capacity. Herein, the synthesis and characterization of two π‐conjugated COFs, derived from the Schiff‐base reaction of 2,4,6‐triaminopyrimidne (TM) respectively with 1,4‐phthalaldehyde (PA) and 1,3,5‐triformylbenzene (TB) by a mechanochemical process are presented. As anode materials for LIBs, the COFs exhibit favorable electrochemical performance with the highest reversible discharge capacities of up to 401.3 and 379.1 mAh g−1 at a high current density (1 A g−1), respectively, and excellent long‐term cyclability with 74.8 and 72.7 % capacity retention after 2000 cycles compared to the initial discharge capacities. [ABSTRACT FROM AUTHOR]

The further development of conducting polymers (CPs) as electrode materials is restricted by the limited doping level, solely ionic reaction as well as the insufficient reversibility and stability. In order to overcome the deficiency of intrinsic properties, a combined strategy is adopted to modify a p‐type CP (polythiophene, PTh) through grafting a radical pendant (2,2,6,6‐tetramethylpiperidinyl‐1‐oxyl, TEMPO) and incorporating a redox‐active dopant (Fe(CN)63−) into the π‐conjugated backbone of PTh. TEMPO group works as the electron donor allowing anionic incorporation (PF6−, ClO4−) and Fe(CN)63− doping in the conducting matrixes of PTh combines with cations (Li+) to deliver extra capacity, leading to the final composite shows a successive cationic and anionic (de)‐intercalation behavior. This dual‐ion transportation mechanism of Fe(CN)63− doped P(Th‐TEMPO) facilitates the enhanced electrochemical performance, including two significant voltage plateaus (3.6 V and 2.9 V), a reversible capacity from 76 mAh g−1 to 135 mAh g−1 at an ultra‐high coulombic efficiency (more than 99 %), which result in a high energy density. [ABSTRACT FROM AUTHOR]

Abstract Using shell-like structures in lithium-ion battery (LIB) can limit the structural degradation/damage induced by the volumetric change during electrochemical cycling. In this work, we synthesize hollow Sn microspheres (Sn-HMSs) via a galvanic replacement reaction, and study the electrochemical performance of the lithium-ion cells with Sn-HMSs as the working electrode. The lithium-ion cells have a charge capacity of 205.9 mA h g−1 after 100 cycles at a current density of 100 mA g−1. In comparison with the charge capacities of 148 mA h g−1 of solid Sn nanospheres and 516.1 mA h g−1 of hollow Sn nanospheres, the results reported in this work reveal the importance of shell-like structures in the retention of the energy storage for LIBs and the size effect on the energy storage. The smaller the hollow Sn spheres, the better is the cycle performance. There are two modes of structural degradation/damage contributing to the capacity loss during electrochemical cycling; one is the disintegration of the Sn-HMSs, and the other is the fracturing of the electrode layer. Highlights • Sn in the Sn-HMSs exhibits tetragonal crystal structure with the size of 3–8 μm. • There are multi-step reactions involving the lithiation and delithiation. • There are two modes of structural degradation/damage contributing to capacity loss. • One structural degradation mode is the disintegration of the Sn-HMSs. • The other structural degradation is the fracturing of the electrode layer. [ABSTRACT FROM AUTHOR]

The recovery of valuable metals from spent lithium-ion batteries (LIBs) is of utmost significance for environmental protection and alleviating resource shortages. Traditional sulfation roasting techniques were accused of their unsustainability and negative environmental impact, such as the consumption of expensive sulfation reagents and the emission of SO 2. This study compared the performance of cobalt-lithium co-sulfation and selective sulfation processes under high and low sulfur input conditions with waste ferrous sulfate as sulfation reagent. The results revealed that selective roasting can efficiently achieve lithium separation without SO 2 emission. Additionally, a sulfation roasting mechanism for SO 2 emission-free conditions under low sulfur input was proposed. At 650 °C, spent lithium cobaltate (LCO) was sulfated via ion exchange with FeSO 4 and gas-solid reactions with SO 2 , and the lithium in the outer layer was selectively sulfated. Partially sulfated CoSO 4 was then served as a sulfation agent to sulfate the unreacted LCO at 800 °C, allowing the sulfur element to be fully recovered and recycled in the form of Li 2 SO 4. By comparing the co-sulfation and selective sulfation processes, an efficient and eco-friendly method for recovering metals from spent lithium-ion batteries was established. [Display omitted] • This study employed the concept of "waste + waste → resources". • Waste copperas as the only additive is used for sulfation roasting of LiCoO 2. • A sulfation roasting mechanism for SO 2 emission-free under low sulfur input was proposed. • Cobalt-lithium co-sulfation and selective sulfation processes were compared. [ABSTRACT FROM AUTHOR]

Abstract: High‐voltage Li2SiO3‐composited LiNi0.5Mn1.5O4 hollow spheres synthesized through a scalable in situ aerosol spray pyrolysis process combined with short‐term high‐temperature calcination are investigated as an ultralong‐life cathode for high‐energy Li‐ion batteries. The phase structure, morphology, and valence state of the LiNi0.5Mn1.5O4/Li2SiO3 composites are investigated by using X‐ray diffraction, electron microscopy, and X‐ray photoelectron spectroscopy. The three‐dimensional Li‐ion conductor Li2SiO3 can effectively enhance the Li+ diffusion rate, alleviate the side reactions, and reduce the formation of a solid electrolyte interphase (SEI) as a protective layer between the LiNi0.5Mn1.5O4 electrode and electrolyte interfaces. Li2SiO3‐composited LiNi0.5Mn1.5O4 has a better rate and cycling performance, especially long cycling performance. After 500 cycles at 25 °C at 1 C, the capacity retention of the composite is 93.28 %, and the capacity retention is 81.23 % after 400 cycles at 50 °C at 1 C rate. The excellent long cycling and capacity retention indicate that the three‐dimensional Li‐ion conductor Li2SiO3 composite with LiNi0.5Mn1.5O4 is a promising material for high‐energy Li‐ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: Spinel LiNi0.45Cr0.1Mn1.45O4 synthesized by a scalable solution route combined by high temperature calcination is investigated as cathode for ultralong‐life lithium‐ion batteries in a wide operating temperature range. Scanning electron microscopy reveals homogeneous microsized polyhedral morphology with highly exposed {100} and {111} surfaces. The most highlighted result is that LiNi0.45Cr0.1Mn1.45O4 has extremely long cycle performance and high capacity retention at various temperatures (0, 25, 50 °C), indicating that Cr doping is a prospective approach to enable 5 V LiNi0.5Mn1.5O4 (LNMO)‐based cathode materials with excellent cycling performances for commercial applications. After 1000 cycles, the capacity retention of LiNi0.45Cr0.1Mn1.45O4 is 100.30% and 82.75% at 0 °C and 25 °C at 1 C rate, respectively. Notably, over 350 cycles at 50 °C, the capacity retention of LiNi0.45Cr0.1Mn1.45O4 can maintain up to 91.49% at 1 C. All the values are comparable to pristine LNMO, which can be attributed to the elimination of LiyNi1−yO impurity phase, highly exposed {100} surfaces, less Mn3+ ions, and enhancement of ion and electron conductivity by Cr doping. Furthermore, an assembled LiNi0.45Cr0.1Mn1.45O4/Li4Ti5O12 full cell delivers an initial discharge capacity of 101 mA h g−1, meanwhile the capacity retention is 82.07% after 100 cycles. [ABSTRACT FROM AUTHOR]

Spent lithium-ion batteries (LIBs) are essential secondary resource, containing valuable metal elements including lithium, cobalt, nickel, manganese. Recovering valuable metals from spent LIBs is significant for achieving environmental protection and alleviating resource shortages. Herein, a sustainable and facile process for Li 2 CO 3 and Mn 2 O 3 recovery from spent LiMn 2 O 4 batteries (LMO) was proposed via sulfation roasting with waste copperas. The leaching efficiencies of Li and Mn reached approximately 100 % and 82 % under the optimal conditions, and the final recovered products were Li 2 CO 3 and Mn 2 O 3 with high purities. The sulfation reaction between LMO and copperas was the transition from solid-solid to gas-solid reaction. During the sulfation reaction, LMO spinel structure was decomposed into MnO 2 and Mn 2 O 3 crystal structures, and the anti-fluorite structure Li 2 O embedded in the spinel structure was released. The Li 2 O was easily to be sulfated, while MnO 2 was partly reduced by Fe2+ to more stable spinel structure Mn 2 O 3. Furthermore, FeSO 4 decomposed into SO 2 gas, which greatly improved the sulfation reaction through permeating into the unreacted core of LMO. As a result, the spinel structure of Mn 2 O 3 was broken, and Mn was escaped to combine with SO 4 2- to form MnSO 4. This research provided an alternative technological route for green recovery of spent LMO batteries, demonstrating high potential for broad application. [Display omitted] • An environmentally friendly approach for recycling LiMn 2 O 4 battery was proposed. • This study employed the concept of "waste + waste → resources". • Waste copperas as the only additive is used for sulfation reaction of LiMn 2 O 4. • The mechanism of the sulfation reaction of LiMn 2 O 4 was investigated. [ABSTRACT FROM AUTHOR]

Polythiophene-coated porous silicon core-shell nanospheres (Si@PTh) composite are synthesized by a simple chemical oxidative polymerization approach. The polythiophene acts as a flexible layer to hold silicon grains when they are repeatedly alloying/dealloying with lithium during the discharge/charge process. The long lifespan and high-current-density rate ­capability (at a current of 8 A g−1) of the Si@PTh composite are vastly improved compared with as-prepared Si spheres. Typically, these Si@PTh composite electrodes achieve a reversible capacity of 1130.5 mA h g−1 at 1 A g−1 current density after 500 cycles, and can even possess a discharge capacity up to 451.8 mA h g−1 at 8 A g−1. The improved electrochemical performance can be ascribed to the synergy effects of the flexible PTh coating and the distinctive core-shell nanospheres with porous structure, which can largely alleviate the volume expansion of the Si during alloying with lithium. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) titanium dioxide@germanium (TiO2@Ge) core-shell nanorod arrays on carbon textiles are fabricated by a facile two-step method and further investigated as flexible electrode for Li-ion batteries (LIBs). The synthesis of TiO2@Ge composite involves the hydrothermal growth of TiO2 nanorod arrays on carbon textiles and a subsequent coat with a thin layer of germanium with radio frequency (RF) magnetron sputtering. The TiO2 nanorod arrays can effectively not only increase the unit mass loading as a role of skeleton but also remarkably enhance the electrical conductivity via control the lithiation/delithiation voltage in the range of 0.01-1.0 V, where TiO2 can be in situ lithiated to LixTiO2 after the first discharge cycle. Moreover, each TiO2@Ge nanorod has enough space to accommodate the large volume expansion of Ge during charge and discharge cycles. Benefiting from unique electrode architectures, this additive free, self-supported electrode exhibits the high reversible capacity, outstanding rate capability, and the extremely long cycling stability even at a high rate (700.3 mAh g−1 is still retained at 5 A g−1 after 600 cycles). [ABSTRACT FROM AUTHOR]

Despite the significant advancement in preparing metal oxide hollow structures, most approaches rely on template-based multistep procedures for tailoring the interior structure. In this work, we develop a new generally applicable strategy toward the synthesis of mixed-metal-oxide complex hollow spheres. Starting with metal glycerate solid spheres, we show that subsequent thermal annealing in air leads to the formation of complex hollow spheres of the resulting metal oxide. We demonstrate the concept by synthesizing highly uniform NiCo2O4 hollow spheres with a complex interior structure. With the small primary building nanoparticles, high structural integrity, complex interior architectures, and enlarged surface area, these unique NiCo2O4 hollow spheres exhibit superior electrochemical performances as advanced electrode materials for both lithium-ion batteries and supercapacitors. This approach can be an efficient self-templated strategy for the preparation of mixed-metal-oxide hollow spheres with complex interior structures and functionalities. [ABSTRACT FROM AUTHOR]

Despite the significant advancement in preparing metal oxide hollow structures, most approaches rely on template-based multistep procedures for tailoring the interior structure. In this work, we develop a new generally applicable strategy toward the synthesis of mixed-metal-oxide complex hollow spheres. Starting with metal glycerate solid spheres, we show that subsequent thermal annealing in air leads to the formation of complex hollow spheres of the resulting metal oxide. We demonstrate the concept by synthesizing highly uniform NiCo2O4 hollow spheres with a complex interior structure. With the small primary building nanoparticles, high structural integrity, complex interior architectures, and enlarged surface area, these unique NiCo2O4 hollow spheres exhibit superior electrochemical performances as advanced electrode materials for both lithium-ion batteries and supercapacitors. This approach can be an efficient self-templated strategy for the preparation of mixed-metal-oxide hollow spheres with complex interior structures and functionalities. [ABSTRACT FROM AUTHOR]

In the work, a facile yet efficient self-sacrifice strategy is smartly developed to scalably fabricate hierarchical mesoporous bi-component-active ZnO/ZnFe2O4 (ZZFO) sub-microcubes (SMCs) by calcination of single-resource Prussian blue analogue of Zn3[Fe(CN)6]2 cubes. The hybrid ZZFO SCMs are homogeneously constructed from well-dispersed nanocrstalline ZnO and ZnFe2O4 (ZFO) subunites at the nanoscale. After selectively etching of ZnO nanodomains from the hybrid, porously assembled ZFO SMCs with integrate architecture are obtained accordingly. When evaluated as anodes for LIBs, both hybrid ZZFO and ZFO samples exhibit appealing electrochemical performance. However, the as-synthesized ZZFO SMCs demonstrate even better electrochemical Li-storage performance, including even larger initial discharge capacity and reversible capacity, higher rate behavior and better cycling performance, particularly at high rates, compared with the single ZFO, which should be attributed to its unique microstructure characteristics and striking synergistic effect between the bi-component-active, well-dispersed ZnO and ZFO nanophases. Of great significance, light is shed upon the insights into the correlation between the electrochemical Li-storage property and the structure/component of the hybrid ZZFO SMCs, thus, it is strongly envisioned that the elegant design concept of the hybrid holds great promise for the efficient synthesis of advanced yet low-cost anodes for next-generation rechargeable Li-ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: Co3O4/MWCNTs composites have been synthesized by a simple hydrothermal method using a surfactant (CTAB) and a precipitation agent (urea). The samples were characterized by XRD, SEM and BET methods. The electrochemical properties of the samples as anode materials for lithium batteries were studied by EIS and Galvanostatic measurements. The Co3O4/MWCNTs composites displayed higher capacity and better cycle performance in comparison with the Co3O4 nanosheets. The remarkable improvement of electrochemical performance within the hybrid composites is probably related to the addition of MWCNTs that possesses improved properties such as excellent electric conductivity and large surface area, which helps to alleviate the effect of volume change, shorten the distance of lithium ion diffusion, facilitate the transmission of electron and keep the structure stable. [Copyright &y& Elsevier]

In this work, we rationally designed an efficient template-free synthetic strategy to fabricate hierarchical mesoporous hollow ZnMn2O4 sub-microspheres (HZSMs) constructed entirely from nanoparticle (NP) building blocks of size ≈15 nm. The well-known inside-out Ostwald ripening process was tentatively proposed to shed light on the formation mechanism of the mesoporous hollow nano-/microarchitecture. In favor of the intrinsic structural advantages, these resulting HZSMs exhibited superior electrochemical lithium-storage performance with high specific capacity, excellent cyclability, and good rate capability when evaluated as an anode material for advanced Li-ion batteries (LIBs). The excellent electrochemical performance should be reasonably ascribed to the porous and hollow structure of the unique HZSMs with nanoscale subunits, which reduced the diffusion length for Li+ ions, improved the kinetic process and enhanced the structural integrity with sufficient void space for tolerating the volume variation during the Li+ insertion/extraction. These results further revealed that the as-prepared mesoporous HZSMs would be a promising anode for high-performance LIBs. [ABSTRACT FROM AUTHOR]

Here, germanium (Ge) nanofilm as the high-capacity electrode was deposited on the three-dimensional porous nickel foam substrate by radio frequency sputtering. Then, cyclized-polyacrylonitrile (PAN) was coated on the surface of Ge nanofilm to get the excellent rate capability and cycle stability owing to the poor cycle life of the as-prepared Ge nanofilm. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy were employed to analyze the microstructure and morphology of the Ge/cyclized-PAN electrodes. The Ge/cyclized-PAN manifests excellent electrochemical performance with high specific capacity and good cycling stability due to the unique structural features. At the charge-discharge rate of 0.1, 0.2, 0.5, 1, 2, and 5 C over a voltage window of 0.01-1.0 V, the discharge capacities of the composite are 731, 722, 701, 676, 621, and 566 mAh g, respectively. The specific capacity retention is up to 98 % with less capacity fading after 100 cycles at 1 C. [ABSTRACT FROM AUTHOR]

Current battery technologies are known to suffer from kinetic problems associated with the solid-state diffusion of Li+ in intercalation electrodes materials. Not only the use of nanostructure materials but also the design of electrode architectures can lead to more advanced properties. Here, advanced electrode architectures consisting of carbon textiles conformally covered by Li4Ti5O12 nanocrystal are rationally designed and synthesized for lithium ion batteries. The efficient two-step synthesis involves the growth of ultrathin TiO2 nanosheets on carbon textiles, and subsequent conversion into spinel Li4Ti5O12 through chemical lithiation. Importantly, this novel approach is simple and general, and it is used to successfully produce LiMn2O4/carbon composites textiles, one of the leading cathode materials for lithium ion batteries. The resulting 3D textile electrode, with various advantages including the direct electronic pathway to current collector, the easy access of electrolyte ions, the reduced Li+/e− diffusion length, delivers excellent rate capability and good cyclic stability over the Li-ion batteries of conventional configurations. [ABSTRACT FROM AUTHOR]

Li-rich layered LiNiMnO has been surface modified by nickel-manganese composite oxide (NiMnO) to serve as a novel cathode material with novel layered spinel structure for lithium-ion battery. The as-prepared LiNiMnO before and after surface modification by NiMnO as well as simply blended LiNiMnO with spinel LiNiMnO, have been characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electronic microscopy, and differential scanning calorimetry. Electrochemical studies indicate that the NiMnO surface modified LiNiMnO with peculiar layered spinel character dramatically represented increased discharge capacity, improved cycling stability as well as excellent rate capability at high-voltage even up to 5.0 V. [ABSTRACT FROM AUTHOR]

Abstract: A simple approach to synthesize Co3O4 in mass production by using surfactant (CTAB) and cosurfactants (C5H12O and C8H12O) via the microemulsion treatment has been developed. By changing the reaction times, the prepared Co3O4 was readily regulated in its morphologies varying from the chrysanthemum-like microspheres in bud to in full bloom. The sample reacted for 6h maintains 565.5mAh·g−1 after 30cycles at a current density of 60mA·g−1, and 495.1mAh·g−1 after 40cycles at a current density of 80mA·g−1. Although the cycling performance at a current density of 50mA·g−1 started to fall off in the initial 20cycles, the capacities were still comparable to the theoretical capacity of graphite (372mAh·g−1) after more than 100cycles. The above 95% capacity retention after 20cycles is believed to benefit from unique structural features, particularly clusters of nanofibers. The chrysanthemum-like nanostructures with larger BET specific surface area created an easier and shorter diffusion pathway for ionic and electronic diffusion, which resulted in good power performance. [Copyright &y& Elsevier]

Abstract: A simple hydrothermal treatment was developed to synthesize Co3O4 powders with different morphologies in mass production by using hexamethylenetetramine (HMT, C6H12N4) as a precipitator. By changing the initial HMT concentrations, the prepared Co3O4 powders were readily regulated in its morphologies, which varied from microsphere to urchin-like hollow microsphere, and finally to collapsed porous structure. Moreover, the four Co3O4 powders with different HMT concentrations had been applied in the negative electrode materials for lithium ion batteries, which exhibited different electrochemical properties. The present research demonstrated that morphology was one of the crucial factors that affected the electrochemical properties of electrodes. The capacity retention of sample with an original Co(NO3)2:HMT mole ratio of 1:1 is almost above 94% from the 5th cycle at different current densities of 40 and 60mAg−1, exhibiting the better long-life stability and favorable electrochemical behaviors due to its higher specific surface area (97.1m2 g−1) and the uniform urchin-like hollow structure. [Copyright &y& Elsevier]

Abstract: A simple approach to synthesize Co3O4 in mass production by using hexamethylenetetramine (HMT, C6H12N4) as a precipitator via hydrothermal treatment has been developed. The samples were calcinated at different temperatures ranging from 300 to 600°C and characterized by XRD and SEM. The structure became agglomerative and collapsed with an increase in calcination temperature. Evaluation of the electrochemical performance in combination with SEM and BET analysis suggests that there is an optimum calcination temperature for Co3O4. It is found that the retention capacity of well crystallized Co3O4 hollow microspheres has a higher specific surface area at 300°C and is almost above 94% after the 5th cycle at different current densities of 40 and 60mAg−1, which shows good long-life stability and favorable electrochemical behaviors. Using EIS analysis, we demonstrated that lithium-ion conduction inside the SEI layers and charge transfer at the electrode/electrolyte interface became hindered with an increased calcination temperature, which was in good agreement with the electrochemical behaviors of three Co3O4 electrodes. It is proposed that drastic capacity fading and the variation of resistive components (SEI layers and charge transfer) can be influenced by morphologies due to the calcination temperature. [Copyright &y& Elsevier]

Highlights: The synthesis strategies of nanohollow carbon materials, including nanospheres, nanopolyhedrons, and nanofibers are summarized. Nanohollow carbon materials used as electrode materials in several types of rechargeable batteries are reviewed. The challenges being faced and perspectives of nanohollow carbon materials are discussed. Among the various morphologies of carbon-based materials, hollow carbon nanostructures are of particular interest for energy storage. They have been widely investigated as electrode materials in different types of rechargeable batteries, owing to their high surface areas in association with the high surface-to-volume ratios, controllable pores and pore size distribution, high electrical conductivity, and excellent chemical and mechanical stability, which are beneficial for providing active sites, accelerating electrons/ions transfer, interacting with electrolytes, and giving rise to high specific capacity, rate capability, cycling ability, and overall electrochemical performance. In this overview, we look into the ongoing progresses that are being made with the nanohollow carbon materials, including nanospheres, nanopolyhedrons, and nanofibers, in relation to their applications in the main types of rechargeable batteries. The design and synthesis strategies for them and their electrochemical performance in rechargeable batteries, including lithium-ion batteries, sodium-ion batteries, potassium-ion batteries, and lithium–sulfur batteries are comprehensively reviewed and discussed, together with the challenges being faced and perspectives for them. [ABSTRACT FROM AUTHOR]

Although silicon is considered as one of the most promising anode materials in next‐generation lithium‐ion batteries, large volumetric expansion during cycling hampers its practical application. The fabrication of silicon/carbon composites is an effective way to improve electrical conductivity and inhibit electroactive material delaminating from the current collector. Herein, a graphitic carbon‐coated porous silicon nanospheres (p‐SiNSs@C) composite is prepared through a chemical vapor deposition (CVD) technique by using the magnesiothermic reduction by‐product MgO as a template and catalyst. With the template of in situ generation of MgO, the p‐SiNSs@C material is obtained in a very short time. Due to the graphitic carbon shell and porous structure inside the silicon nanospheres, the obtained p‐SiNSs@C, with 8 min carbon growing time (p‐SiNSs@C‐2), deliver a high initial reversible capacity of 2220 mAh g−1 at 0.1 A g−1 and respectable rate capability. Furthermore, the p‐SiNSs@C‐2//LiCoO2 Li‐ion full cell displays a high energy density of ≈409 Wh kg−1 and good cycling performance. The high performance of the p‐SiNSs@C‐2 composite can be attributed to the synergistic effect of nanoscale‐sized Si, porous structure, and stable carbon shell. [ABSTRACT FROM AUTHOR]

A highly graphitized carbon on a silicon monoxide (SiO) surface coating at low temperature, based on polymer precursor π–π stacking, was developed. A novel conductive and electrochemically stable carbon coating was rationally designed to modify the SiO anode materials by controlling the sintering of a conductive polymer, a pyrene-based homopolymer poly (1-pyrenemethyl methacrylate; PPy), which achieved high graphitization of the carbon layers at a low temperature and avoided silicon carbide formation and possible SiO material transformation. When evaluated as the anode of a lithium-ion battery (LIB), the carbon-coated SiO composite delivered a high discharge capacity of 2058.6 mAh/g at 0.05 C of the first formation cycle with an initial Coulombic efficiency (ICE) of 62.2%. After 50 cycles at 0.1 C, this electrode capacity was 1090.2 mAh/g (~82% capacity retention, relative to the capacity of the second cycle at 0.1 °C rate), and a specific capacity of 514.7 mAh/g was attained at 0.3 C after 500 cycles. Furthermore, the coin-type full cell composed of the carbon coated SiO composite anode and the Li[Ni0.5Co0.2Mn0.3O2] cathode attained excellent cycling performance. The results show the potential applications for using a π–π stacking polymer precursor to generate a highly graphitize coating for next-generation high-energy-density LIBs. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Porous Sn@AB microspheres with AB being dispersed in Sn are synthesized. • Electrochemical cycling induces self-assembling of Sn and AB to form microflowers. • Prolonged electrochemical cycling leads to the closure of cracks of Sn@AB MSs. Abstract We report a facile route to synthesize porous Sn nanocrystals@acetylene black microspheres (Sn@AB MSs) via a galvanic replacement reaction of Zn microspheres in a SnCl 2 solution consisting of acetylene black (AB). The half cells of lithium-ion batteries with the Sn@AB MSs as the working electrode have a charge capacity of 480.8 mA h g−1 at 100 mA g−1 after 100 cycles, and the charge capacity of the half cells after the 100th cycle is slightly larger than that after the 80th cycle. The SEM images reveal that the electrode layer from the Sn@AB MSs experiences surface cracking during electrochemical cycling, while prolonged cycling leads to the closure of cracks. Electrochemical cycling induces self-organization of Sn and AB to form rose-like porous Sn@AB/Li 2 SnO 3 microflowers from porous Sn@AB MSs. The closure of cracks and formation of porous Sn@AB/Li 2 SnO 3 microflowers likely cause the increase of the charge capacity. The experimental results demonstrate that the porous Sn@AB MSs with acetylene black around Sn can alleviate the large volumetric strain due to lithiation/delithiation, reduce the migration distance of lithium to active sites, and promote exceptional Li storage, leading to better cycling stability. [ABSTRACT FROM AUTHOR]

In this work, we successfully designed and synthesized Ge nanoparticles encapsulated in a carbon matrix and supported by three-dimensional interconnected porous N-doped carbon foam (3D Ge/C-NCF) nanoarchitecture. When applied as an anode material for lithium ion batteries, the obtained composite electrode exhibits high capacity of 878.1 mAh g −1 at a current density of 0.5 A g −1 after 150 cycles. Additionally, it also achieves excellent rate capability and cycling stability. The significant improved electrochemical performance of Ge/C-NCF can be attributed to the synergetic effects of the carbon matrix and the N-doped carbon framework: including a highly conductive carbon network and a structure with large porous for mitigates volume changes of Ge nanoparticles. This study of the composite electrode may provide an interesting method to creating efficient and practical electrodes for those that suffer from huge volume expansion for energy storage applications. [ABSTRACT FROM AUTHOR]

Abstract: Nitrogen-doped carbon coated Li4Ti5O12 (NC–LTO) nanocomposite as an anode material for lithium-ion batteries (LIBs) is prepared with acetyl glucosamine as carbon source by pre-coating process combined with ball milling. X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy are used to characterize the NC–LTO materials. The results show that NC–LTO samples exhibit the obvious improvements in rate capability and cycling performance compared with the LTO samples coated by carbon (C–LTO) derived from sugar and pure LTO samples. The carbon pre-coating process could significantly decrease the agglomeration of TiO2 precursors and the uniformly coated nitrogen-doped carbon increase the interfacial stability and electric conductivity of LTO. At the charge–discharge rate of 0.2 C, 5.0 C and 10.0 C and 20.0 C, the discharge capacities of NC–LTO samples are 167.4, 146.3, 133.4 and 128.2 mAh g−1, respectively. After 1000 cycles at 1 C, its capacity retention is 95.9% with nearly ignored capacity fading. [Copyright &y& Elsevier]

Abstract Recently, CoCO 3 is attracting extensive interests as a promising anode for Li-ion batteries (LIBs) thanks to its large capacities and simple synthesis. However, its modest electrochemical behaviors and ambiguous lithium storage mechanisms still need to be well addressed. Herein, we devise a scalable bottom-up solvothermal methodology to fabricate monodispersed pinecone-like CoCO 3 sub-microspheroids constructed with nanosheet subunits. When evaluated as appealing anode for LIBs, the resultant CoCO 3 anode exhibits high initial Coulombic efficiency of ∼75.2%, and large reversible capacity of ∼1008 mAh g−1 at a rate of 200 mA g−1, and even ∼663 mAh g−1 at 2 A g−1, benefiting its hierarchical micro-/nanostructures. Besides, the enhanced interfacial charge-storage capability of the CoCO 3 sub-microspheroids with cycling accounts for the long-duration capacity retention of ∼138% over 500 consecutive cycles. More significantly, comprehensive lithium storage mechanism of the CoCO 3 , involving conventional conversion reactions, reversible redox reaction of low-valence C/C(IV), and debut observation of reversible Co(II)/Co(III) transition, is proposed with in-situ and ex-situ physicochemical and electrochemical investigations. Furthermore, a CoCO 3 //LiNi 0.8 Co 0.15 Al 0.05 O 2 full battery is assembled and delivers prominent electrochemical properties, hugely highlighting the enormous potential of our CoCO 3 sub-microspheroids in next-generation LIBs as competitive anodes. Graphical abstract Monodispersed hierarchical CoCO 3 sub-microspheroids were scale-up fabricated and displayed superior electrochemical behaviors. More significantly, intrinsic lithium storage mechanisms were proposed as a competitive anode towards Li-ion batteries. Image 1 Highlights • A solvothermal method was devised to fabricate CoCO 3 sub-microspheroids. • The monodispersed sub-microspheroids were constructed with nanosheets. • The resultant CoCO 3 anode exhibited superior Li-storage behaviors. • The comprehensive lithium-storage mechanism of CoCO 3 was proposed. • A CoCO 3 -based full device with prominent Li-storage properties was assembled. [ABSTRACT FROM AUTHOR]

Li 4 Ti 5 O 12 with long cycling life has been deemed to be one of the most promising anode materials for lithium ion battery. Nevertheless, poor electronic conductivity impedes its application for energy storage. Meanwhile MXene possesses high electrical conductivity and moderate electrochemical energy storage. Herein, we develop a novel strategy for the in-situ synthesis of layered-stacked Li 4 Ti 5 O 12 -MXene composite. The synergistic effect of Li 4 Ti 5 O 12 and MXene greatly improved the electrochemical properties of Li 4 Ti 5 O 12 -MXene composite. At a high current density of 10 A g − 1 , a high discharge capacity of 116 mAh g − 1 can be achieved. Moreover, a high discharge capacity of 178 mAh g − 1 after 500 cycles can be maintained at a current density of 5 A g − 1 . This work demonstrates a scalable route to assemble MXene-derived Ti-based materials for high-performance electrochemical energy storage applications. [ABSTRACT FROM AUTHOR]

A sustainable yet massive synthesis of porous micro-/nano-structured spinel mixed metal oxides is highly desirable as advanced anodes for their extensive applications in rechargeable lithium-ion batteries (LIBs). In this contribution, a self-sacrifice biomorphic template-engaged strategy was purposefully devised for efficient and scalable fabrication of hierarchical porous ZnMn 2 O 4 micro-belts (ZMO-MB). The synthetic procedure mainly involves impregnating natural cotton fibers with Mn 2+ /Zn 2+ ions, followed by sacrificing template over calcination in air. The underlying formation process of the ZMO-MB was rationally put forward with comparative analysis. Physicochemical investigations showed that the well-defined ZMO-MB with hierarchical meso-/macro-porosity was composed of assembled nanoparticle subunits. Taking advantages of intrinsic structural and functional merits, the resultant ZMO-MB with a mass loading of ∼1.2 mg exhibits appealing Li-storage properties with large reversible capacity (∼436 mAh g −1 at 2000 mA g −1 ), high initial Coulombic efficiency (∼71.2%) and appealing long-duration cyclability at high rates (∼731 mAh g −1 after 150 cycles at 500 mA g −1 ) when evaluated as a promising anode platform for high-performance LIBs. More encouragingly, we strongly envision that the smart electrode design concept here can be easily for large-scale production and engineering of promising ZMO for next-generation LIBs. [ABSTRACT FROM AUTHOR]

High energy density batteries and high power density supercapacitors have attracted much attention because they are crucial to the power supply of future portable electronic devices, electric automobiles, unmanned aerial vehicles, etc. The electrode materials are key components for batteries and supercapacitors, which influence the practical energy and power density. Metal-organic frameworks possessing unique morphology, high specific surface area, functional linkers, and metal sites are excellent electrode materials for electrochemical energy storage devices. Herein, we review and comment on recent progress in metal-organic framework-based lithium-ion batteries, sodium-ion batteries, lithium-air batteries, lithium-sulfur/selenium batteries, and supercapacitors. Future perspectives and directions of metal-organic framework-based electrochemical energy storage devices are put forward on the basis of theoretical knowledge from the reported literature and our experimental experience. [ABSTRACT FROM AUTHOR]

Monoclinic MgF 2 and C co-coated Li 3 V 2 (PO 4 ) 3 (LVP) has been investigated as long life cathode of lithium-ion battery. The X-ray diffraction (XRD) results reveal that MgF 2 modification has not changed the structure of LVP/C. The high resolution transmission electron microscopy (HRTEM) shows that the thickness of the uniform amorphous hybrid coating is about 10 nm. The research shows that the novel co-coating significantly enhanced the electrochemical performance of LVP cathode material, which is attributed to synergistic effect between MgF 2 and C coating. MgF 2 layer can restrain the dissolution of V element and enhance the structural stability of LVP in the electrolyte. Meanwhile, the presence of the carbon coating enhances the electron conductivity. The electrochemical impedance spectroscopy (EIS) further demonstrates that the hybrid coating is beneficial for structural stability of LVP/C during cycling. In conclusion, it can be speculated that the hybrid coating of MgF 2 and C should be an effective strategy to enhance the electrochemical performance of LVP. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new synthesis of TiO2/nitrogen-doped reduced graphene oxide nanocomposite. [•] Nitrogen-doping can significantly improve the conductivity of graphene. [•] Nitrogen-doped graphene is valuable in promoting electron transfer. [•] The TiO2/N-RGO exhibits superior rate capability and cycle stability. [Copyright &y& Elsevier]

Abstract: Spinel Li4Ti5O12 nanorods coated with poly (3,4-ethylenedioxythiophene) (PEDOT) layer as an anode material for lithium ions battery were synthesized by a facile soft chemistry approach. The highly conductive and uniform PEDOT layer coated on the surface of Li4Ti5O12 nanorods significantly improves the electrochemical performance of the composite, which exhibits higher reversible capacity and better rate capability compared with the pure Li4Ti5O12 and Li4Ti5O12/C composite. The reversible capacity of Li4Ti5O12/PEDOT nanorods can be up to 171.5mA h g−1 at the rate of 0.2C. And a capacity of 168.7mA h g−1 was retained with only 0.5% capacity loss after 100 charge-discharge cycles at the rate of 1C, which confirms the good cycling behavior of Li4Ti5O12/PEDOT nanorods. The superior electrochemical performance of the Li4Ti5O12/PEDOT nanorods could be attributed to the one-dimensional (1D) morphology and uniform conducting polymer layer, which shortens the lithium-ion diffusion path and improves the electrical conductivity of Li4Ti5O12. [Copyright &y& Elsevier]