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Ultra-high nickel layered cathode materials with very high specific capacity are the future direction of power battery development, but they also face many challenges such as poor cycling stability and high-rate performance. In this paper, we adopt an effective Mo/PANI co-modification strategy on a LiNi0.96Co0.02Mn0.02O2 (NCM9622) cathode material and achieve excellent electrochemical performances. The optimized modified NCM9622 cathode material can reach 209.3 mA h g−1 with an upper cut-off voltage of 4.4 V at 1C, and its capacity retention reaches 95.7% after 100 cycles, which exceeds that of similar materials reported so far. In addition, the material also has outstanding high-rate properties, and its discharge specific capacity reaches 167.1 mA h g−1 at 10C. The excellent electrochemical properties are well demonstrated by the results of Li+ migration barriers and electronic density of states (DOS) calculated by density functional theory (DFT). We believe that the cooperative modification strategy of high-valence ion doping and conductive polymer coating will provide technical support for solving the key problems of ultra-high nickel cathode materials. [ABSTRACT FROM AUTHOR]

LiNiO2 cathode material for lithium‐ion batteries has the advantages of high specific capacity, abundant resources, and low cost, but it suffers from difficulties in preparation, structural instability, and serious capacity decay. In this work, highly pure and layered structural LiNi0.95AlaTi0.05‐aO2 (a=0, 0.025, 0.05) cathode materials were synthesized by a simply sol‐gel method. The cation mixing of Ni2+ and Li+, structural deterioration, irreversible conversion between H2 and H3 phases and unstable surface and CEI (Cathode‐electrolyte interface) film can be effectively suppressed by co‐doping with Al3+ and Ti4+. A preferred LiNi0.95Al0.025Ti0.025O2 sample provides a discharge specific capacity of 223 mAh g−1 at 0.1 C and 148.32 mAh g−1 at 5 C, a capacity retention of 72.7 % after 300 cycles at 1 C and a Li+ diffusion coefficient of about 2.0×10−9 cm2 s−1. [ABSTRACT FROM AUTHOR]

Due to the urgency of developing high energy density cathode materials in power batteries, as well as the high price and environmental unfriendliness of cobalt, researchers are working on ultra-high nickel low cobalt and ultra-high nickel cobalt-free layered cathode materials. However, the poor cyclic stability and rate performance of this material resulted from structural instability and severe surface/interface side reactions during cycling seriously hinder its practical application. In this paper, LiNi0.9Mn0.1O2 (NM90) cathode material is modified by La2O3 coating, and La3+ doping caused by thermal diffusion is achieved simultaneously. The synergistic enhancement of the two modifications can effectively improve the layered structure and reduce surface/interface side reactions. The dual-modified material shows good structural stability, the La2O3 coating does not fall off and the active material does not appear fragmentation and collapse after 100 cycles. At the same time, the dual-modified material also shows excellent electrochemical performance, with a capacity retention of 83.19% after 100 cycles at 1 C and a reversible capacity of 129.9 mAh g−1 at 10 C. The electrochemical mechanism reveals that the dual-modified material effectively reduces the charge transfer resistance and greatly increases the Li+ diffusion coefficient. It will provide useful reference and technical support for the research of other electrode materials. The NM90 and La2O3-coated NM90 particles have similar spherical morphology and are formed by the agglomeration of many primary particles; the surface of NM90 material is evenly coated by La2O3 and No obvious boundary between La2O3 and NM90 materials is found; LiNi0.9Mn0.1O2 cathode material coated by 1wt% La2O3 has the best cycle stability. [ABSTRACT FROM AUTHOR]

The electrochemical performances and process mechanisms of Zn/LiFePO4 cells in a slightly acidic 1.9 m Li2SO4–0.5 m ZnSO4 aqueous solution were investigated. The results showed that the hydrogen depletion side reaction on the surface of the zinc sheet led to an increase in pH of the electrolyte and fluctuations in specific capacity of the cells, and that the dissolution of Fe2+ ions and the lamination of LiFePO4 particles resulted in a decrease in the specific capacity of the cells. At pH 5.0, the initial discharge specific capacity of the Zn/LiFePO4 cell was about 120.0 mAh g−1 at 0.25 C, about 64.4 mAh g−1 at 3 C, with about 60.9 % capacity retention rate after 200 cycles at 1 C, and the Li+ ions diffusion coefficient was about 7.75×10−12 cm2 s−1. [ABSTRACT FROM AUTHOR]

Monodisperse SnO2/Co3O4 nanocubes are designed and prepared via a thermally induced phase separation. X-ray diffraction measurement reveals that the composite is composed of SnO2 and Co3O4 phases. Scanning electron microscopy and transmission electron microscopy bring insight into the morphology of the nanocubes, which have a size of 100–200 nm and consist of tightly contacted SnO2 and Co3O4 grains with a size of 20–30 nm. X-ray photoelectron spectroscopy indicates that the SnO2 and Co3O4 are chemically bound with each other. Comparative study in electrochemical properties is implemented among the SnO2/Co3O4 nanocubes, pure SnO2, Co3O4, and physical mixture of SnO2 and Co3O4. Electrochemical characterizations suggest that the SnO2/Co3O4 nanocomposite has remarkably enhanced electrochemical reversibility, cycling stability, rate capability, and faster charge-transfer than the others. The results highlight the synergistic effect derived from the Sn–Co binding in electrochemical Li-ion storage. In addition, the phase separation method is considered as an effective way to produce heterojunctions within binary or ternary composites. [ABSTRACT FROM AUTHOR]

The dually decorated Na3V2(PO4)2F3 by in‐situ formed carbon and three‐dimensional graphene (NVPF/C@3DG) is prepared via two hydrothermal steps and a high‐temperature calcination. Benefiting from the high electronic conductivity of carbon and 3DG, high surface area and the resulted high diffusion coefficients of Na+, NVPF/C@3DG displays superior electrochemical performance to the control NVPF/C. Between 2.5 and 4.5 V (vs. Na+/Na), NVPF/C@3DG presents the initial discharge capacity of 123.6 mAh g−1 at 0.2 C (25.6 mA g−1) and capacity retention of 92.1 % after 60 cycles, while NVPF/C shows initial discharge capacity of 119 mAh g−1 and capacity retention of 84.1 % under the identical test conditions. Even at 15 C, the initial discharge capacity and capacity retention after 1000 cycles of NVPF/C@3DG are as high as 91.2 mAh g−1 and 82.9 %, respectively, much better than the initial discharge capacity of 71.2 mAh g−1 and the corresponding capacity retention of 76.4 % for NVPF/C, respectively. [ABSTRACT FROM AUTHOR]

Sn doped ZnFe2O4 samples were prepared by co-precipitation method. It is found that with the increase of Sn content, the phase structure of the prepared samples transformed from single-phase spinel ZnFe2O4 to two-phase ZnFe2O4/SnO2 composite and the particle size of samples decreased; The Sn doped ZnFe2O4 (with Sn/Fe ratio of 0.05) exhibited the best lithium storage performance among the four samples. For example, after 300 cycles at 1000 mA g−1, the Sn doped ZnFe2O4 (with Sn/Fe ratio of 0.05) delivered a reversible capacity of 1163 mA h g−1, much higher than that (715 mA h g−1) of the undoped ZnFe2O4. [ABSTRACT FROM AUTHOR]

V2O5·nH2O/graphene composites have been fabricated via a facile sol–gel method followed with an annealing treatment in air. The influence of incorporation of graphene on the microstructure and sodium storage performance of V2O5·nH2O were investigated. XRD, Raman, and TGA analyses validated that graphene was successfully incorporated in V2O5·nH2O particles; XPS tests revealed that the incorporation of graphene induced more V4+ in the V2O5·nH2O. When evaluated as cathode materials for sodium-ion batteries (SIBs), the V2O5·nH2O/graphene composites exhibited higher sodium storage capacity, better rate capability, enhanced Na+ diffusivity, and lower electrochemical reaction resistance as compared to the pure V2O5·nH2O. However, the incorporation of graphene had no improvement of the cycling stability of V2O5·nH2O. Ex situ XRD demonstrated that the layered structure of V2O5·nH2O collapsed upon cycling, which accounts for the capacity decay of the samples. [ABSTRACT FROM AUTHOR]