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Lithium-ion batteries (LIBs) are greatly limited in their practical application because of their poor cycle performance, low conductivity and volume expansion. Herein, molten salts (MSs) FeCl3·6H2O-NMP with low temperature via simple preparation are used as the anode material of LIBs for the first time to break through the bottleneck of LIBs. The good fluidity and high self-healing of FeCl3·6H2O-NMP effectively avoid the collapse and breakage of the structure. Based on this feature, the initial discharge specific capacity reached 770.28 mA h g-1, which was more than twice that of the commercial graphite anode. After 200 cycles at a current density of 100 mA g-1, the specific capacity did not decrease rather it was found to be higher than the initial discharge specific capacity, reaching 867.24 mA h g-1. Besides, the good conductivity of MSs provides convenience for the removal and intercalation of Li+. The active H sites that can combine with lithium ions form LiH and provide capacity for LIBs. Density functional theory (DFT) calculation also provided theoretical proof for the mechanism of LIBs. [ABSTRACT FROM AUTHOR]

In this investigation, a lithium-free cathode material, Na0.7MnO2.05–Na0.91MnO2, was synthesized by the solid phase method. The intercalation mechanism and partial phase transformation mechanism of NMO600 were clarified by in situ X-ray diffraction and impedance. The design of the heterostructure is favourable for improving the lithium ion storage of NMO600, which can deliver a discharge capacity of 83.12 mA h g−1 at 1 A g−1 and keep 61.71 mA h g−1 after 700 cycles. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2) is a very useful catalytic material for energy storage. However, the design and synthesis of special morphologies is required to overcome the poor cycle stability of such materials. We synthesized MoS2 composites embedded with silica using a chemical vapor deposition (CVD) technique and silica nanotemplates and obtained a honeycomb MoS2 nanomaterial with a stable structure and extremely thin single walls. Results of methods including SEM and XRD revealed that honeycomb MoS2 formed a three-dimensional hollow structure in the bulk phase. With this structure, more spatial positions are exposed during lithium-ion storage, meaning it can accommodate higher energy and facilitate the transmission of lithium ions. The honeycomb MoS2 developed in this study was demonstrated to have a high capacity and structural stability. The reversible capacity was as high as 680 mA h g−1 after 100 cycles, which is still higher than the theoretical capacity of MoS2 (670 mA h g−1), with the coulombic efficiency exceeding 99%. Furthermore, the capacity remained at ∼600 mA h g−1 at the 2C rate, demonstrating a superior rate capability. Our study will provide a contribution for studies including the synthesis of MoS2 with special morphology and the optimization of nanomaterials for energy storage. [ABSTRACT FROM AUTHOR]

TiO2 is a promising and safe anode material for lithium-ion batteries. Nevertheless, its inferior electronic conductivity and inferior cycling capability have always limited its practical application. In this study, flower-like TiO2 and TiO2@C composites are produced by a simple one-pot solvothermal method. It is noticeable that the synthesis of TiO2 is carried out simultaneously with carbon coating. The flower-like TiO2 with a special morphology can decrease the distance of lithium ion diffusion, while the carbon coating improves the electronic conductivity of TiO2. At the same time, the carbon content of TiO2@C composites can be controlled by adjusting the amount of glucose. Compared with flower-like TiO2, TiO2@C composites have higher specific capacity and preferable cycling performance. It is noteworthy that the specific surface area of TiO2@C with a carbon content of 63.36% is 293.94 m2 g−1 and its capacity remains at 371.86 mAh g−1 after 1000 cycles at 1 A g−1. Other anode materials can also be prepared using this strategy. [ABSTRACT FROM AUTHOR]

A straightforward carbothermal reduction method was used to synthesize nitrogen-doped carbon-coated LiFePO4 with the carbon and nitrogen sources derived from gelatin. Compared to the bare material, the particles of LiFePO4 composites are smaller, the electrical contact between the grains is improved, and lithium ions diffuse more rapidly in the composites. As a consequence, the structural stability and conductivity are enhanced in LiFePO4 compounds. After 500 cycles, the material delivered 138.2 mA h g−1 at a multiplicity of 1C with 90.2% capacity retention. This result demonstrates that a suitable amount of N-doped carbon layer can enhance the electrochemical performance of LiFePO4. This efficient strategy provides a facile approach to develop excellent performance LiFePO4 materials with promising practical applications. [ABSTRACT FROM AUTHOR]

Lack of high-performance active materials limits the rapid development of advanced energy storage devices with both high power and high-energy performance. Here, Mn3O4/reduced graphene oxide (RGO) was synthesized as a negative material for both lithium-ion batteries (LIBs) and lithium-ion capacitors (LICs). The RGO prevents the aggregation of Mn3O4 and enhances the charge transport rate, enabling Mn3O4/RGO to exhibit high specific capacity, superior rate performance, and long cycling stability. More significantly, the charge storage of Mn3O4/RGO is mainly from the surface controlled reaction, which accounts for 58.2–83.3% of charge storage capacity when the scan rate increases from 0.1 to 1.0 mV s−1. Owing to high specific capacity and fast reaction kinetics of Mn3O4/RGO, the composite exhibits high energy performance when assembled with a LiNi0.5Co0.2Mn0.3O2 cathode, and achieves both high-energy and high-power performance in LICs after being assembled with activated carbon (AC). The LiNi0.5Co0.2Mn0.3O2//Mn3O4/RGO LIB displays a specific energy of 144.8 W h kg−1 at 215.1 W kg−1, and the AC//Mn3O4/RGO LIC exhibits a specific energy of 98.6 W h kg−1 at 180.1 W kg−1 with a retained specific energy of 70.3 W h kg−1 at a high specific power of 1937.5 W kg−1. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2), with its unique two-dimensional nanostructure and high theoretical capacity, is considered a promising electrode for lithium-ion batteries (LIBs). However, the disadvantages of MoS2 electrodes include low electronic conductivity, sluggish cation kinetics, serious volume change, poor cycle stability, and inefficient rate performance of lithium storage. Herein, oxygen vacancy and heterostructure engineering are rationally involved in revealing the moderate oxygen vacancy in the hierarchical tubular heterostructure material (MoS2@MoO2) via a self-template method as a highly active LIB electrode. Due to the presence of the moderate oxygen vacancies and heterojunction structure of MoS2@MoO2-4, the diffusion pathway and barrier for lithium ions can be significantly reduced, accelerating the ionic diffusion rate and further promoting the reaction kinetics. The electrode achieves a high reversible capacity of 1200.1 mA h g−1 at 100 mA g−1 after 100 cycles with the optimum regulation of the sulfur contents and the moderate oxygen vacancy (MoS2@MoO2-4). Additionally, good rate capability is obtained at stepwise current densities due to the merits of MoS2@MoO2. A series of measurements such as EPR, XPS, in situ XRD, and in situ Raman are also employed to reveal the synergistic effect in the midst of oxygen vacancies and heterostructures for lithium storage. All results prove that the moderate oxygen vacancy and tubular heterostructure can implement faster Li+ transport and lower the diffusion barrier of lithium ions, resulting in enhanced lithium storage performance of MoS2@MoO2. [ABSTRACT FROM AUTHOR]

As the economy started to recover from the COVID pandemic, the price of Li2CO3 skyrocketed to its highest. This situation has aggravated concerns about the supply chain for lithium-ion batteries (LIBs). Recycling spent LIBs is a potential solution to alleviate the bottleneck of the supply chain and prevent environmental pollution, and has attracted lots of attention. However, lithium recycling is generally disregarded because of the complex recycling process and its low recycling efficiency. Here, in this work we developed a sustainable lithium recovery process, which can selectively leach and recover lithium with formic acid before recycling valuable metals. With the reported method, lithium can be 99.8% recovered from layered oxide cathode materials with 99.994% purity. In addition, this lithium recovery process is affordable, compared to the typical hydrometallurgical process, by saving 11.15% per kilogram of spent LIBs. Therefore, this research provided a new solution to eliminating the effects of lithium ions on valuable metal separation and the co-precipitation reaction and precluding the influence of other metal ions on lithium recovery. This simplified lithium recovery process provides new opportunities for sustainable recycling of LIBs and economical restoration of the lithium supply chain. [ABSTRACT FROM AUTHOR]

SiOx is one of the most promising anode materials for lithium-ion batteries (LIBs), due to its high theoretical capacity and low cost. However, the huge volume expansion and low electron/ion diffusion rate hinder its further commercial applications. Herein, a simple molecular polymerization method is developed to synthesize N,P co-doped SiOx–C composites (denoted as SiOx–C@CNT), in which SiOx and carbon are uniformly dispersed at the atomic level, and the embedded carbon nanotubes improve the lithium ion diffusion kinetics. Benefiting from the unique structure, the SiOx–C@CNT composites exhibit a high reversible capacity of 848 mA h g−1 at 0.1 A g−1 and long cycling stability (84.0% capacity retention after 1500 cycles). More impressively, the LiCoO2∥SiOx–C@CNT full battery also exhibits stable cycle life (only 4.7% capacity loss after 300 cycles at 1 C). These results show the application potential of the SiOx–C@CNT anode in LIBs. [ABSTRACT FROM AUTHOR]

In view of the disadvantage of the limited active site utilization due to the easy aggregation of phthalocyanine compounds, three kinds of graphene composite metal phthalocyanines (TN-MPc@GN, M = Fe, Co, Ni) were prepared using an in situ composite method, and their electrochemical properties were investigated as anode materials for lithium-ion batteries. The layered structure and large specific surface area of graphene are used to disperse phthalocyanine uniformly, so that the conjugated structure (C＝C/C＝N/N＝O) of phthalocyanine is more exposed and the utilization of active sites for embedding lithium ions are greatly enhanced. At the same time, the large surface area is beneficial to the contact between materials and the electrolyte, which results in a faster transmission path. As a result, the first discharge specific capacities of the graphene composite phthalocyanine (TN-MPc@GN, M = Fe, Co, Ni) electrodes are 440.8, 765.0 and 753.9 mA h g−1, respectively. After 420 cycles, the specific capacities increased to 734.6, 844.7 and 949.1 mA h g−1, respectively, which are much higher than those of the pristine three phthalocyanine (TN-MPC, M = Fe, Co, Ni) electrodes without the graphene composite. Using the graphene composite can be an effective strategy to improve the utilization of active sites of organic electrode materials in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Single-phase magnesium molybdate, MgMoO4, is successfully synthesized by a facile sol-gel method. Attributed to the multielectron reaction and the synergistic effect of the elements molybdenum (Mo) and magnesium (Mg), the MgMoO4 electrode exhibits excellent electrochemical properties. After activation, benefiting from the decrease in particle size and the uniform nanosphere morphology, the MgMoO4 electrodes can deliver a stable high specific capacity of about 1060 mA h g−1 at a current density of 100 mA g−1 after 600 cycles. Based on the important role of the activation process, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and scan rate cyclic voltammetry (CV) measurement methods were employed to reveal the effect of the activation process on the electrochemical behavior of the electrode material. Furthermore, by combining the in situ X-ray diffraction (XRD) and ex situ X-ray photoelectron spectroscopy (XPS) results, we illustrate the lithium storage mechanism of the MgMoO4 electrode in detail. [ABSTRACT FROM AUTHOR]

Fe-Doped ZnFexCo2−xO4 (x = 0.00, 0.17, 0.33, 0.47, 0.67, 0.87, 1.17, 1.37, 1.67, 1.87, 2.00) compounds were prepared by a sol–gel method. X-ray diffraction measurements show that Fe-doping does not change the crystal structure of ZnCo2O4 and dopant Fe successfully occupies the 16c Co site. Because of the bigger radius of the doping ion, the cell parameters and cell volumes of ZnFexCo2−xO4 compounds present an obvious linear increase with increasing Fe content. In addition, attributed to the similar crystal structures for ZnFe2O4 and ZnCo2O4, a full range (0 ≤ x ≤ 2) of ZnFexCo2−xO4 solid solution phases was obtained. V/I measurement results show that a small Fe doping content obviously improved the electronic conductivity of the sample. In addition, due to the smaller particles size and uniform particle distribution caused by Fe doping, the lithium ion diffusion coefficient of the sample was increased by 2 orders of magnitude. Based on the improved electronic conductivity combined with the significantly increased lithium-ion diffusion coefficient, a sample with Fe doping content of x = 0.33, ZnFe0.33Co1.67O4, presents a high reversible specific capacity and excellent rate cycle stability. At a rate of 100 mA g−1, a relatively high discharge capacity of 850 mA h g−1 can still be obtained after 100 cycles, which is obviously higher than that of pure ZnCo2O4 (only 295 mA h g−1). Even at a higher discharge rate of 500 mA g−1, a discharge capacity of 450 mA h g−1 with a capacity retention of nearly 100% was obtained. Based on its excellent electrochemical properties, ZnFe0.33Co1.67O4 will be a promising anode material for rechargeable lithium-ion batteries. [ABSTRACT FROM AUTHOR]

In order to develop novel fast charge/discharge carbon anode materials, an organic hard carbon material (PTCDA-1100) is obtained by calcination of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) at a high temperature of 1100 °C. The obtained PTCDA-1100 sample has a disordered porous nanostructure, large specific surface area, and more exposed active points, providing channels for the rapid transport of lithium ions. As a result, the PTCDA-1100 electrode shows superior lithium storage behavior compared to conventional commercial graphite materials when used as a negative anode material for lithium-ion batteries. When the PTCDA-1100 electrode is charged and discharged at the small current rate of 0.2C, the initial capacity of the electrode is 320.7 mA h g−1, which is very close to that of graphite (329.5 mA h g−1). However, as the cycles increase, after 100 cycles, the capacity of the PTCDA-1100 electrode is 290.9 mA h g−1 with a retention rate of 90.7%, which are significantly higher than the capacity of graphite (231.3 mA h g−1) and its retention rate of 70.2%. Similarly, at all other high current rates of 1C, 3C and 5C, the PTCDA-1100 electrode is significantly better in both capacity and cycle stability than the commercial graphite electrode. Overall, the PTCDA-1100 organic hard carbon materials prepared in this work show better cyclic stability and rate capability both in half and full batteries compared to commercial graphite material, which would provide new ideas for developing novel carbon negative materials for fast charge and discharge of lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Transport phenomena and the solvation structure of lithium ions (Li+) and hexafluorophosphate anions (PF6−) in electrolytes with different fluoroethylene carbonate (FEC) concentrations as well as the electrochemical performance and safety of Ni-rich Li-ion battery cells at the 18650 cylindrical cell level are investigated. We have found that the electrolyte with an optimized FEC concentration (25% v/v) can effectively enhance the transport property in terms of the Li+ transference number and contact ion pair (CIP) ratio leading to high performance and safety of practical 18650 cylindrical LIBs. [ABSTRACT FROM AUTHOR]

In this study, a hydrothermal reduction route was applied for the controlled production of MnOOH nanohydrangeas and MnOOH nanorods. The structure and morphology of the formed products were characterized. Both MnOOH nanohydrangeas and nanorods were utilized as active anodes for Li-ion batteries. Galvanostatic charge–discharge, cyclic voltammogram, rate performance, and electrochemical impedance were analyzed to compare the lithium ion energy storage performances of the two MnOOH nanostructures. The results indicate that γ-MnOOH nanorods possess enhanced cycle and rate capacity compared with the γ-MnOOH nanohydrangeas. At a current density of 200 mA g−1, a specific capacity of 965 mA h g−1 is obtained for the formed γ-MnOOH nanorods after 200 cycles, while the reversible capacity of MnOOH nanohydrangeas is 380 mA h g−1, which suggests that the morphology variation of the as-prepared MnOOH nanostructures can influence the electrochemical properties. γ-MnOOH nanorods synthesized by this method present a prospective application for lithium ion batteries. [ABSTRACT FROM AUTHOR]

Lithium iron phosphate (LFP) has become one of the current mainstream cathode materials due to its high safety and low price. Most modification methods applied (e.g. ion doping, carbon coating and particle size restriction) are used to overcome its poor electronic and ionic conductivity. Here, the Y–F co-doped LFP/carbon (LFP/C) precursor was successfully synthesized using a high temperature solid phase method. The electronic conductivity of the material is enhanced by doping with F which induces the rearrangement of the PO43+ electron cloud, while the doping with Y introduces Li+ vacancies, thereby reducing the space resistance of Li ion diffusion, resulting in an overall enhancement of the ionic conductivity of the material. In addition, XRD refinement results show that Y and F doping leads to a weakening of the Li–O bond while also widening the lithium ion diffusion tunnel, thereby increasing the lithium ion diffusion rate. Therefore, this work has produced LFP/C-YF-2, which exhibits an ultra-high discharge specific capacity of 135.8 mAh g−1 at 10C, and a discharge specific capacity of 148.6 mA h g−1 without attenuation after 700 cycles at 5C. It is hoped that this high-capacity and high-rate cycling stability material will become a promising cathode material for applications in high-power electric vehicles and other equipment. [ABSTRACT FROM AUTHOR]

Rational engineering of the microstructure and interfacial properties of nano-metal oxides materials is critical to realize their practical use in batteries. This work reports a detailed study on how structural and chemical interplay in a robust 3D crumpled MXene protected SnO2 core–shell system contributes to performance as an anode in lithium-ion batteries. Our results show that the compact conductive MXene shell can provide robust protection against the large volume change and aggregation of SnO2, providing excellent structural stability. Further analyses show that rich surface groups on the MXene can not only enable strong interfacial interactions through Sn–O–Ti bonds to grant electrical contacts, but also provide a pseudocapacitive contribution for fast and stable lithium storage. Furthermore, a conformal SEI formed outside the MXene can build a stable protective interface and prevent further consumption of electrolyte simultaneously. As a result, the SnO2@MXene composite delivered a high specific capacity of 829.4 mAh g−1 at a current density of 0.2 A g−1, and exhibited an excellent cycling stability (533.9 mAh g−1 after 500 cycles at 1 A g−1). The strategy reported here for synthesizing a core–shell MXene based material can be promising for the development of high-performance anode materials for next-generation LIBs. [ABSTRACT FROM AUTHOR]

Structural knowledge on ubiquitous lithium salts in solution and in the crystalline state is of paramount importance for our understanding of many chemical reactions and of the electrolyte behaviour in lithium ion batteries. A bulky bidentate Si-based ligand (6) was used to create simplified model systems suitable for correlating structures of LiCl and LiPF6 complexes in the solid-state and in solution by combining various experimental, spectroscopic, and computational methods. Solution studies were performed using 1H DOSY, multinuclear variable temperature NMR spectroscopy, and quantum chemical calculations. [Ph2Si(2-CH2Py)2·LiCl]2 (3) dissociates into a monomeric species (9) in THF. For [Ph2Si(2-CH2Py)2·LiPF6]2 (11), low temperature NMR studies revealed an unprecedented chiral coordination mode (12) in non-coordinating solvents. [ABSTRACT FROM AUTHOR]

As a promising anode candidate, silicon (Si) nanoparticles have been widely studied for use in lithium ion batteries. However, Si nanoparticles suffer from the disadvantage of volume expansion during lithiation/delithiation, which leads to irreversible capacity decrease. In this work, perlite is utilized to prepare Si nanoparticles via magnesiothermic reduction. To alleviate the volume expansion of Si nanoparticles, a nanoporous carbon is prepared to coat Si nanoparticles using chitosan (C) as the carbon source and zinc chloride (Z) as the pore former. TEM micrographs show that the porous carbon with mesoporous size has formed and coated the surface of Si nanoparticles. The prepared carbon coated Si sample (Z-C@Si-5 contains 5 times the mass ratio of Z to C) exhibits suitable pore volume (0.576 cm3 g−1) and pore size (4–6 nm), as well as excellent specific surface area (418.315 m2 g−1) The obtained Z-C@Si-5 also shows promising electrochemical performance with a reversible capacity of 2064.11 mA h g−1 at 0.2C and 847.32 mA h g−1 at 4C, as well as a high capacity retention. The promising electrochemical performance originated from the nanoporous carbon coating, which not only effectively alleviated the volume expansion problem of Si, but also provided a rapid transport channel of lithium ions through its nanoporous structure. [ABSTRACT FROM AUTHOR]

Sulfur atoms can reconstruct the configuration of PAN, which makes the electron transfer more convenient and reduces the energy barriers during Li ion diffusion. The sulfurized polyacrylonitrile plays a crucial role in anchoring the P4 molecule and electron transport simultaneously. Uniform RP nanoparticles (∼200 nm) are obtained using a simple liquid phase method. SPAN–RP shows an initial reversible capacity of 1214 mA h g−1 at 0.2C and retains a capacity of 860 mA h g−1 with a high coulombic efficiency of 99.6% after 200 cycles. [ABSTRACT FROM AUTHOR]

Ilmenite FeTiO3 has the advantage of high theoretical capacity and abundant sources as an anode material for lithium-ion batteries (LIBs). However, it suffers inferior rate capability caused by the aggregation of particles. To solve this problem, FeTiO3 nanoparticles embedded in porous CNTs were developed by the sol–gel route and subsequent calcination. The unique hybrids have a uniform distribution of FeTiO3 nanoparticles (5–20 nm) in the carbon matrix. Electrochemical tests prove that the porous FeTiO3/C hybrid nanotubes deliver a high capacity of 612.5 mA h g−1 at 0.2 A g−1 after 300 cycles. Moreover, they present remarkable rate capability and exceptional cycling stability, possessing 163.8 mA h g−1 at 5 A g−1 for 1000 cycles. The enhanced electrochemical performance of the FeTiO3/C hybrid is derived from the shortened Li+ transport length, good structure stability and conductive carbon matrix, which simultaneously solves the major problems of pulverization and agglomeration of FeTiO3 nanoparticles during cycling. [ABSTRACT FROM AUTHOR]

In this work, a Ni/NiO/nitrogen-doped carbon (Ni/NiO/NC) nanocomposite was synthesized by a simple pyrolysis of a [Ni(Schiff base)] complex. The formation of the nanocomposite was confirmed by X-ray diffraction, Raman and Fourier transform infrared spectroscopy studies. X-ray photoelectron spectroscopy analysis revealed the chemical state of the elements present in the Ni/NiO/NC composite. Combining the merits of a supercapacitor and battery into a hybrid, a supercapattery device was fabricated in the form of a CR-2032 coin cell consisting of Ni/NiO/NC as the positive electrode and reduced graphene-oxide (rGO) as the negative electrode. The supercapattery device exhibited a high specific energy of 37 W h kg−1 at a specific power of 560 W kg−1 and high specific power of 2750 W kg−1, while the energy density was as high as 18 W h kg−1 with excellent cycling stability as well as coulombic efficiency. In addition, the lithium-ion storage performance of the Ni/NiO/NC nanocomposite was examined in half-cell and full-cell configurations. The full-cell exhibited a reversible capacity as high as 400 mA h g−1 with an attractive cycling stability and coulombic efficiency. The excellent electrochemical performance was attributed to the large surface area and the conductive carbon network, which facilitates ion/electron transport with the shortened diffusion path. [ABSTRACT FROM AUTHOR]

N-doped three-dimensional carbon nanostructured materials were obtained by calcinating hierarchical porous IRMOF-3 materials, and were fabricated in the presence of citric acid as a modulator via the conventional synthetic protocol, at 900 °C in an Ar atmosphere. The resultant carbon materials were used as anode materials for lithium ion batteries, and exhibited excellent lithium storage capacity and cycling stability and maintained a capacity of about 555 mA h g−1 at the current density of 0.2 A g−1 after 100 cycles. [ABSTRACT FROM AUTHOR]

Alginate dressings can be used as a new type of lithium-ion battery separator with high thermal stability, excellent electrolyte adsorption/retention ability, and environmental friendliness, showing a broad application prospect in high safety lithium ion batteries. [ABSTRACT FROM AUTHOR]

Herein, Cu-doped Co-ZIF nanoplate arrays are uniformly grown on a commercial paper towel substrate first. After a subsequent annealing treatment, well-defined Cu-doped Co/CoO nanoparticles embedded in N-doped carbon hybrid nanoplate arrays supported on the carbon paper substrate (denoted as Cu-doped Co/CoO/NC NPAs@CP) are obtained, which exhibit excellent performance as a low-cost, lightweight and binder-free anode for lithium ion storage. [ABSTRACT FROM AUTHOR]

Cation doping is one of the most dynamic strategies to enhance the electrochemical properties of cathode materials for lithium-ion batteries. Nevertheless, the maximum partial substitution capacity depends on the solubility of each metal ion, and so the formation of impurities is a very common consequence. Thus, the correlation between electrochemical performance and the doping effect is frequently unknown. In this study, the effect of the partial substitution of copper by manganese, iron or nickel in Li2CuO2 is evaluated, as well as the effect on the electrochemical performance of the modified Li2CuO2 samples as lithium ion battery cathode materials. XRD characterization confirmed single phase formation for all samples, and the incorporation of the transition metal in the Li2CuO2 structure was evaluated by XRD profile fitting, EPR and 7Li-NMR. The results showed modifications in intra- and inter-chain interactions, associated with the variations in the Cu–O–Cu bond angle and changes in magnetic order, due to the presence of the doping transition metal. Among all samples, only manganese partial substitution reveals a drastic improvement in the electrochemical stability during the charge/discharge processes even at potentials higher than 3.9 V. It was corroborated that the higher stability is attributed to (i) the increase in the superexchange interactions between the copper sites and manganese, directly modifying lithium diffusivity and electronic conductivity, both inferred from dynamic thermogravimetric analysis for CO2 sorption and conductivity tests, respectively and (ii) the lower propensity to enable O2 evolution during several charge cycles. These results are totally attributed to manganese cation partial substitution, which has a huge impact on the utilization of copper-based materials in real applications. [ABSTRACT FROM AUTHOR]

LiNi0.8Co0.1Mn0.1O2 is one of the most promising cathode materials for lithium ion batteries; however, during the charge/discharge process, it suffers from capacity fading, which is considered to be due to intergranular cracking. Herein we develop an original concept to alleviate this problem via negative pressure immersion treatment. A 3D-SiO2 framework is formed in the intergranular voids and at grain boundaries (functioning as the buffer zone and transfer-bridge) and the SiO2 protective layer is completely and homogeneously coated on the surfaces of the pristine particles through a hydrolytic condensation reaction involving tetraethoxysilane (TEOS). The 3D-SiO2 framework has two advantages: firstly, acting as a buffer zone, the framework can effectively inhibit the generation and extension of intergranular cracking; secondly, like the SiO2 protective layer on the surface of the particles, the 3D-SiO2 framework can impede side reactions between primary particles (grains) and electrolyte inside the particles. As a result, the as-modified LiNi0.8Co0.1Mn0.1O2 exhibits enhanced cycling performance with 92.4% capacity retention after 100 cycles at 1 C (200 mA h·g−1), while the capacity retention values for the pristine particles and normal coating treatment particles are only 55.4% and 82.6%, respectively. Moreover, the thermal stability (60 °C) is distinctly enhanced and the rate performance is significantly improved at high rates (2, 3 and 5 C). [ABSTRACT FROM AUTHOR]

SnO2@C nanocomposites were synthesized using a citrate gel method in one step. Carbon has been used to increase the conductivity of pristine SnO2. The SnO2@C nanocomposites show nanoparticles sized in the range of 30–50 nm. A structural study by XRD shows the tetragonal rutile structure of SnO2. Furthermore, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy confirm the existence of SnO2 along with carbon. The electrochemical performance was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge–discharge measurements. The nanocomposite has been used as an anode material for lithium-ion batteries. Pristine SnO2 exhibited a discharge capacity of 1854 mA h g−1 and a corresponding charge capacity of 1038 mA h g−1 for the first cycle. The SnO2@C nanocomposite showed a discharge capacity of 2574 mA h g−1 and charge capacity of 1481 mA h g−1 for the first cycle. These results clearly show the effect of carbon incorporation in SnO2. Furthermore, the nanocomposite shows a discharge capacity as high as 725 mA h g−1 after 200 cycles at a current density of 50 mA g−1. Thus, the obtained capacity for the nanocomposites is much higher as compared to that for pristine SnO2, i.e., 119 mA h g−1 at 50 mA g−1 after 200 cycles. The higher capacity in the nanocomposites is due to the fast transport of electrons and easy transport of lithium ions due to the carbon in the nanocomposites. The SnO2@C nanocomposite anode exhibits superior cycling stability and rate capability due to its stable electrode structure. [ABSTRACT FROM AUTHOR]

Transition metal phosphides have been receiving a great deal of attention as anode materials for Li-ion batteries due to their novel properties of high theoretical capacity and relatively low polarization. MoP and MoP2 nanoparticles with different crystal structures are synthesized by phosphorization in different stoichiometric proportions, using Mo nanospheres as the precursor produced by the plasma evaporation method. When used as the anode material for Li-ion batteries, the MoP2 electrode delivers a stable capacity of 676.60 mA h g−1 after 300 cycles at a current density of 0.1 A g−1 with obvious discharge/charge plateaus; however, the capacity of the hexagonal MoP electrode is 312.38 mA h g−1. The first-principles calculations illustrate that the di-phosphorus bond of MoP2 is prone to break and the distal P atoms preferentially bind with Li atoms to form Li3P during lithiation, but MoP prefers to form ternary LixMoP. The ex situ X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) of the MoP2 electrode after cycling confirm the conversion reaction for the electrochemical storage of Li-ions. [ABSTRACT FROM AUTHOR]

Fluorinated lithium-rich anti-perovskite (F-LiRAP) is proposed to enhance lithium ion conductivity by creating Frenkel defects that facilitate the formation of lithium-rich and lithium-vacancy couples. We successfully demonstrate an all-solid-state cell configuration based on F-LiRAP, precluding the employment of polymer or liquid additives. [ABSTRACT FROM AUTHOR]

To investigate the effects of different crystallinities on the electrochemical performance of V2O5 as an anode material for lithium ion batteries, spherical V2O5 with variable crystallinities was prepared via a solvothermal method and changing the calcination temperature. The results confirmed that V2O5 with lower crystallinity showed a better lithium ion storage performance because of its loose structure, lower polarization, and the convenient diffusion of lithium ions. The reversible specific capacity of V2O5 obtained at 250 °C (1092.1 mA h g−1) with lower crystallinity was much higher than that of the others prepared at 350 °C (645.9 mA h g−1), 450 °C (526 mA h g−1), and 550 °C (498.9 mA h g−1) at 100 mA g−1 after 200 cycles. Also, it maintained a specific capacity of 584.6 mA h g−1 even at 1 A g−1 after 500 cycles. V2O5 prepared at 350 °C exhibited an excellent rate performance with a specific capacity of 131.1 mA h g−1 at a current density of 5 A g−1. The aim of this study was to propose an effective direction and strategy to design traditional metal oxide electrode materials with lower crystallinity to enhance the cycle and rate performance of lithium ion batteries in the future. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) few-layer MXene nanosheets have attracted extensive attention due to their great potential for high-rate energy storage devices, but a simplified method to synthesize these structures with good cycling and rate performances is still a challenge for the MXene family. In this work, a one-step method to synthesize 2D few-layer niobium carbide (Nb2CTx) MXene nanosheets by etching Nb2AlC powder is reported for the first time. A sample of the few-layer Nb2CTx electrode shows a high specific capacity of 354 mA h g−1 at 0.05 A g−1 with a long cycling lifetime. The specific capacity can be stabilized at 225 mA h g−1 after 800 cycles at 1.0 A g−1. The one-step synthesis of unassisted few-layer Nb2CTx MXene nanosheets paves the way for the exploration of Nb2CTx-based composite materials and applications. [ABSTRACT FROM AUTHOR]

This communication reports a novel hyperbranched polymer with poly(ethylene glycol)9 segments and carboxylate groups. The combined advantages of single-ion conduction and a hyperbranched structure make the as-prepared polymers very promising as a solid-state polymer electrolyte for lithium ion batteries, by showing high ionic conductivity up to 1.2 × 10−4 S cm−1 at 85 °C, a high lithium transference number (tLi+) of 0.86, and simultaneously, a stable potential window up to 4.8 V versus Li+/Li. [ABSTRACT FROM AUTHOR]

A robust carbonized cotton cloth interlayer composed of numerous knitted hollow carbon microtubes is simply derived from waste cotton cloth by scalable carbonization. The interlayer acts as an upper current collector and a lithium polysulfide barrier simultaneously, thus greatly improving the electrochemical performances of the lithium–sulfur batteries. [ABSTRACT FROM AUTHOR]

The first molecular solid solution of lithium and sodium ions is reported. In spite of the different chemical and structural properties of the parent compounds, the two cations form a homogeneous mixed phase with the isoorotate ion. Such observation appears in contrast with the Hume-Rothery principles for solid solutions. Furthermore the mixed salts in the series are thermally stable up to 100 °C and non-hygroscopic, which makes them relevant for their potential use as a lithium drug substance. [ABSTRACT FROM AUTHOR]

This paper introduces the in situ topotactic synthesis of a porous network Zn2Ti3O8 platelike nanoarchitecture via using layered H1.07Ti1.73O4·H2O (HTO) as the precursor. The introduction of H2O2 in the interlayer of HTO leads to access of more Zn2+ ions into the interlayers and the formation of the Zn2+ ion-exchanged product with a Zn/Ti molar ratio of 1.07 : 1.73 during ion exchange. This ion-exchanged product is in situ topotactically transformed into a Zn2Ti3O8 nanoarchitecture after heat-treatment, and the [110]-crystal-axis of the Zn2Ti3O8 nanoarchitecture is vertical to the basal plane of the 2D nanoarchitecture. The H2O2 molecule within the ion-exchanged product decomposes and escapes due to heat-treatment, resulting in the formation of a porous network structure similar to a sponge. The pore size is about 10–20 nm. Moreover, the electrochemical investigation indicates that such a porous network Zn2Ti3O8 nanoarchitecture as a Li-ion battery anode has a reversible capacity of 423 mA h g−1 during the 100th cycle at a current density of 100 mA g−1. It is wondrous that at a current density of 1 Ag−1 during 1000 cycles, its reversible capacity still remains at 408 mA h g−1. [ABSTRACT FROM AUTHOR]

With the increasing demand for lithium resources, it is of great significance to develop a new technology for the selective recovery of lithium from complex systems. In the present work, antifouling lithium-imprinted hybrid membranes (LIHMs) were fabricated through a hydrolysis polymerization method using a PVDF/GO hybrid membrane as a basement membrane, and polydopamine as an adhesion layer to anchor imprinted sites. The antifouling experiments demonstrated that LIHMs had the underwater oil contact angle of 152 ± 0.8°. Furthermore, the adsorption isotherms, permeation and adsorption kinetics of the LIHMs were researched in detail. The results displayed that LIHMs showed a distinctive adsorption capacity (27.10 mg g−1) and permselectivity (βK/Li = 5.3780, βCa/Li = 21.9402, βMg/Li = 15.5620) for lithium. Also, the regeneration experiments confirmed the good durability of LIHMs, favoring long-term use. Therefore, the LIHMs provided a powerful tool for the effective separation and recovery of lithium in practical applications. [ABSTRACT FROM AUTHOR]

Hierarchical ZnSn(OH)6/Zn2SnO4 yolk–shell nonspherical structures that are composed of self-supported nanowire arrays have been conveniently prepared via a simple secondary growth method. The XRD and TEM results indicate that the composition of the outer nanowire shell is the Zn2SnO4 (ZTO) phase, while the inner cubic core is the incomplete conversion ZnSn(OH)6 phase. Due to the synergistic effect of the low dimensional shell and stable yolk–shell structure, the as-obtained hierarchical ZnSn(OH)6/ZTO yolk–shell structures exhibit high stability and capacity for lithium ion batteries (LIBs). [ABSTRACT FROM AUTHOR]

Hollow Mn2O3 microspheres have been synthesized by a simple and easy-to-adopt solvothermal method, facilitated by ethanol to obtain the phase pure product at 600 °C. Herein, the ascorbic acid aided inside-out Ostwald ripening promotes the formation of porous microspheres with a hollow interior surface, which is desirable to allow faster transport of lithium ions and to accommodate the volume changes associated with the Mn2O3 anode, especially upon extended cycling. Further, an appreciable high surface area of 426.6 m2 g−1 has been calculated from BET analysis, which is in favour of imparting excellent electrochemical properties that include high reversible capacity, good cycling stability and acceptable rate capability. Interestingly, Mn2O3 hollow microspheres exhibit 425 mA h g−1 under the influence of 1 A g−1 current density, thus qualifying itself as a high rate anode material, bestowed with the added advantage of appreciable high capacity, extractable under nominal current densities. For instance, without requiring the formation of composite, the as-received Mn2O3 anode delivers a steady-state capacity of 760 mA h g−1 at 50 mA g−1 and 610 mA h g−1 at 100 mA g−1, especially after completing 100 cycles. The synergistic advantage of the microspheres containing hierarchically arranged nanostructures and the hollow interior nature with better uptake of the electrolyte results in obtaining promising electrochemical performance from the currently synthesized Mn2O3 anode. [ABSTRACT FROM AUTHOR]

High power density lithium ion battery (HLIB) separators were fabricated for the first time from thermally rearranged poly(benzoxazole-co-imide) (TR-PBOI) nanofibrous membranes coated with TR-PBOI nanoparticles, which show distinct thermal and dimensional stabilities as well as excellent cycle retention and rate capability. [ABSTRACT FROM AUTHOR]

A facile process is developed to synthesize a TiO2-MoS2 nanohybrid via a one-pot hydrothermal route and post-annealing in an Ar atmosphere at 500 °C for 4 h. The precursor and target products were characterized by transmission electron microscopy (TEM) and field-emission scanning electron microscopy (FESEM). TEM and FESEM analysis showed that TiO2 nanoparticles with an average diameter of about 20 nm were uniformly distributed on MoS2 nanosheets. Electrochemical measurements demonstrated that the nano-TiO2-decorated MoS2 nanosheets exhibited excellent cycling stability and rate performance, which delivered a capacity of 604 mA h g-1 after 100 cycles at a current density of 100 mA g-1. The TiO2 is believed to act as a stabilizer to retain the MoS2 structure upon prolonged cycling. This material can be a promising candidate for the lithium ion batteries (LIBs). [ABSTRACT FROM AUTHOR]

Anode materials of rechargeable lithium-ion batteries have been developed towards the aim of high power density, long cycle life, and environmental benignity. As a promising anode material for high power density batteries for large scale applications in both electric vehicle and large stationary power supplies, the spinel Li4Ti5O12 anode has become more attractive for alternative anodes for its relatively high theoretical capacity (175 mA h g-1), stable voltage plateau of 1.5 V vs. Li/Li+, better cycling performance, high safety, easy fabrication, and low cost precursors. This perspective first introduces recent studies on the electronic structure and performance, synthesis methods, and strategies for improvement including carbon-coating, ion-doping, surface modifications, nano-structuring and optimization of the particle morphology of the Li4Ti5O12 anode. Furthermore, practical applications of the commercial spinel lithium-ion batteries are demonstrated. Finally, the future research directions and key developments of the spinel Li4Ti5O12 anode are pointed out from a scientific and an industrial point of view. In addition, the prospect of the synthesis of graphene-Li4Ti5O12 hybrid composite anode materials for next-generation lithium-ion batteries is highlighted. [ABSTRACT FROM AUTHOR]

Spherical anatase mesocrystals have been successfully prepared in an acetic acid–tetrabutyl titanate–benzoic acid system via a facile solvothermal method. Based on the results of time-dependent experiments, a growth process is proposed for the spherical mesocrystals, which includes the formation of flower-like intermediates, the hydrolysis of these intermediates, and the precipitation and self-assembly of TiO2 nanocrystals. Benzoic acid plays an important role in the formation of the spherical morphology. Well-defined spherical anatase mesocrystals can be obtained only when the benzoic acid content is ＞4.5 g. As a result of their unique architecture (high crystallinity and a large specific surface area), the Li ion storage capabilities of these spherical mesocrystals were also investigated. The first discharge capacity is 314.5 mA h g−1 and the corresponding charge capacity is 224.3 mA h g−1, leading to a Coulombic efficiency of 71.3% at 0.2 C. Even under high current densities, such as 2 and 5 C, this anode material retains a good cycling stability and very high specific capacity. [ABSTRACT FROM AUTHOR]

We propose a facile, scalable, yet versatile methodology for the formation of three-dimensional mesoporous (3DMP) tin-based alloy anodes for lithium-ion batteries (LIBs), using cyanogel coordination polymers as precursors for the first time. The synthesis of a 3DMP Sn–Ni alloy network with a high surface area and uniform mesopores has been demonstrated as an example using SnCl4/K2Ni(CN)4 cyanogel as the precursor. After surface carbon coating, the 3DMP Sn–Ni@C network exhibited enhanced lithium storage capabilities by virtue of its unique structural characteristics, such as its excellent structural stability, high charge transport capability, and improved reaction kinetics of lithium insertion/extraction. The proposed synthetic strategy could open up new opportunities for constructing advanced tin-based alloy anodes for LIBs. [ABSTRACT FROM AUTHOR]

Layered Li4NiTeO6 was shown to reversibly release/uptake ∼2 lithium ions per formula unit with fair capacity retention upon long cycling. The Li electrochemical reactivity mechanism differs from that of Li2MO3 and is rooted in the Ni4+/Ni2+ redox couple, that takes place at a higher potential than conventional LiNi1−xMnxO2 compounds. We explain this in terms of inductive effect due to Te6+ ions (or the TeO66− moiety). [ABSTRACT FROM AUTHOR]

Precise knowledge of the discharge and charge reactions within Li–O2 batteries is an important aspect of developing highly efficient, rechargeable Li–O2 cells. We describe an analytical method capable of determining the quantity of Li2O2 in the cathode on the basis of the reaction of Li2O2 with an oxoammonium salt. [ABSTRACT FROM AUTHOR]