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Sea urchin-like LiAlO 2 @NiCoO 2 hybrid composites with core-shell structure assembled with nanoneedles have been successfully fabricated through a facile hydrothermal route followed by a calcination procedure in N 2 for the first time. The sea urchin-like architecture with large accessible surface can offer numerous active sites for redox reaction. The synergy of two advantages has dramatically improved the electrochemical behavior in terms of specific capacity, cycle performance and rate capability, especially at high current densities. The LiAlO 2 (5.0 wt%)@NiCoO 2 displays charge capacities are 1309.0 and 933.6 mAh g−1 at 0.5 and 1A g−1, respectively, after 400 cycles. However, the charge capacities of bare NiCoO 2 are only 562.9 and 476.7 mAh g−1 at corresponding rates. Especially, LiAlO 2 (5.0 wt%)@NiCoO 2 preserves 358.1 mAh g−1 after 500 cycles at 2A g−1 with a capacity retention of 74%. The superior electrochemical property is related to the sea urchin-like nature and the ingenious composition design. In addition, the DFT calculation result shows that the formed stable, well-coordinated, and metallic interface between LiAlO 2 and NiCoO 2 are very helpful for reducing the interfacial impedance and beneficial for the improved rate capability of the materials. Therefore, such LiAlO 2 @NiCoO 2 composites with unique morphology demonstrate a huge potential as electrode materials for Li-ion batteries. [ABSTRACT FROM AUTHOR]

The Li2MoO3 (LMO) material is one promising cathode material for lithium-ion batteries due to its high specific capacity and absence of oxygen release. However, its surface instability in air and poor conductivity have limited its application. To solve these problems, the Ru element has been successfully introduced into the LMO lattice with the aid of the molten salt method. XRD and TEM characterization showed that the introduction of Ru does not change the crystal structure but expands the crystal plane spacing of the {001} facets, which is further evidenced by density functional theory (DFT) calculations. XPS and EDS tests indicated that the introduction of Ru inhibits the oxidation of Mo species and leads to a more uniform distribution of the material. In addition, DFT calculations revealed that covalent interactions are formed between Mo4d/Ru4d and O2p orbitals, leading to a significant reduction of the band gap. Therefore, Ru-doped samples exhibit good electrochemical performances. The initial discharge capacity of an LMRO-2 sample reaches 299.1 mA h g−1 at a 1C rate, and the capacity remains at 125.2 mA h g−1 after 100 cycles. In comparison, the initial discharge capacity of pure phase sample LMO is only 250.5 mA h g−1 under the same conditions, and the capacity remains only at 76.5 mA h g−1 after 100 cycles. The present results confirmed that Ru doping is an effective strategy to improve the performance of the LMO cathode material. [ABSTRACT FROM AUTHOR]

ZnTiO3 and ZnTiO3–CeO2 microspheres with particle sizes of about 100–300 nm were synthesized for the first time by a simple solvothermal process followed by calcination. The results indicate that CeO2 modification does not alter the morphology of the microspheres. ZnTiO3–CeO2 (0, 3, 6, and 9 wt%) show an initial charge (discharge) capacity of 171.01 (253.2), 204.6 (507.5), 213.4 (451.6) and 126.2 (367.2) mA h g−1 at 500 mA g−1, respectively. After 500 cycles, the corresponding charge (discharge) capacities were 191.1 (192.3), 298.7 (300.3), 322.4 (328.5) and 211.2 (212.3) mA h g−1, respectively. Obviously, the charge (discharge) capacities of the ZnTiO3–CeO2 composites are superior to those of pristine ZTO, which demonstrates that the Li storage performance of the CeO2-modified ZTO electrodes is improved. The CeO2 shell provides a good electronic contact between ZnTiO3 and CeO2, decreasing charge transfer resistance and facilitating the charge transportation of the ZnTiO3–CeO2 composite. In addition, the formed phase interface between CeO2 and ZnTiO3 may provide more active sites for electrochemical reactions, improving the reversibility of Li-ion intercalation and decreasing the electrochemical polarization during cycling, especially at high current densities. Therefore, such ZnTiO3–CeO2 microspheres can be regarded as hopeful candidates for anode materials for Li-ion batteries. [ABSTRACT FROM AUTHOR]

Li 2 ZnTi 3 O 8 @ α -Fe 2 O 3 composites have been successfully prepared by a facile hydrothermal process. Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composites show similar irregular spherical morphologies like Li 2 ZnTi 3 O 8 and relatively smaller particle sizes than pristine Li 2 ZnTi 3 O 8. Among all Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composites, Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composite (5 wt%) exhibits the best electrochemical properties. Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composite (5 wt%) delivers a reversible charge capacity of 184.8 mAh g−1 even at 1000 mA g−1 after 500 cycles, while pristine Li 2 ZnTi 3 O 8 only delivers a reversible charge capacity of 110.7 mAh g−1. The strong covalent bonds between Li 2 ZnTi 3 O 8 and α-Fe 2 O 3 will be formed, which is beneficial for the reduction of interfacial energy and thus helpful for the stabilization of the composite. Because of the special synergistic effect of the multi-phase interface, Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composites not only possess the advantages of single components but also show novel and attractive performances, such as the enhanced ionic conductivity, reduced interfacial charge transfer impedance, improved migration rate of lithium ions, and the enhancement of the rate performance and reversible capacity. The as-prepared Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composites reveal important potentials as anode materials for next-generation rechargeable Li-ion batteries, and this work also offers an effective strategy to design high performance lithium storage materials for advanced lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Li 2 MoO 3 (LMO) is a promising stabilization block for constructing high performance lithium-rich layered oxides. However, its poor electronic conductivity, surface instability in air, and capacity degradation are drawbacks for the application. To solve these issues, non-equivalent Nb5+ dopants were introduced into the LMO lattice. Density functional theory (DFT) calculations combined with experimental characterizations have confirmed that Nb5+ doping not only enhances the Mo–O bonds of LMO but also reduces its band gap and further suppresses the oxidation of surface Mo4+, leading to a much-improved lattice and surface stabilities. Therefore, the electrochemical performances of LMNO are improved obviously. The initial discharge capacities of LMO, LMNO-0.01, LMNO-0.02, and LMNO-0.03 are 232.6, 234.7, 251.6, and 246.3 mAh·g−1, respectively. LMNO-0.02 exhibits the best performance, and its specific capacities at the 1st and 100th cycles reach 144.13 and 72.06 mA g−1 under a 3C charging rate and a 5C discharging rate. Our results have demonstrated that non-equivalent cationic doping is an effective strategy to modulate the bonding characteristics of LMO and therefore to improve its electrochemical performance. [ABSTRACT FROM AUTHOR]

Due to its special Z-shaped layered structure, Na 2 Ti 3 O 7 has great potential as an anode material for lithium-ion battery application. However, the poor electrical conductivity and cycle life have seriously affected its application in practice. In this paper, we prepared a sea urchin shaped Na 2 Ti 3 O 7 material by a simple hydrothermal method. This special morphology allows the material to have a large specific surface area, which can better contact with the electrolyte and increase the active site number. The half-cells assembled with sea urchin-like Na 2 Ti 3 O 7 show excellent cycling performance and good rate performance. After 1000 cycles at a 1 C rate, the specific capacity of NTO maintains at 70%. Even at a 5 C rate, NTO-2 delivers a discharge capacity of 71 mAh g−1 after 1000 cycles. The method proposed can be extended to other new anode materials to boost their electrochemical performances. [Display omitted] • Na 2 Ti 3 O 7 with a large specific surface area was prepared by a one-step hydrothermal method. • Morphology of the materials was optimized by regulating the PH of the solution. • The effect of morphology on the electrochemical properties of the materials was revealed. [ABSTRACT FROM AUTHOR]

[Display omitted] • LNMTO sample exhibits the excellent cycling stability at high temperature in half cells and full cells. • The relevance of Ti4+ doping and safety of LNMO as cathode material was revealed from aspects of structure stability and evaluated temperature properties by experimental and theoretical study. • The enhancement mechanism on safety by Ti4+ doping was put studied. The proposal of net-zero emissions policy promotes the research on safety property of cathode material in lithium ion batteries. Herein, to improve the safety of high voltage LiNi 0.5 Mn 1.5 O 4 (LNMO) as cathode material in lithium ion batteries, Ti4+ ions were doped into LNMO(LNMTO) and the enhancement mechanisms on safety property were investigated from aspects of structure stability and elevated-temperature properties by experimental and theoretical study. In experimental, the influence of Ti4+ doping on cathode/electrolyte interface stability and cathode thermal stability is explored by differential scanning calorimetry test(DSC), thermal diffusion and In-situ-XRD. Ti4+ doping can effectively improve the structure-stability of LNMO by infusing the stronger Ti-O bands, promoting thermal diffusion and suppressing the unexpected two-phase reactions. Compared with LNMO, LNMTO exhibits superior cycling stability at elevated-temperature with the 100th capacity of 124.1 mAh·g−1, which is equal to 98.8% of the 1st discharge capacity under 2C at 55 °C. Furthermore, we also verified the effectiveness of Ti4+ doping on improving thermal stability in LNMO/Li 4 Ti 5 O 12 (LTO) full cells. This work systematically investigates the effect of Ti4+ doping on safety of LNMO from aspects of structure-stability and elevated-temperature properties, which can be easily stretched into other cathode materials and speed up wider application of LIBs. [ABSTRACT FROM AUTHOR]

By using cheap, stable, relative low-toxic precursors (the key of the design), a nanocomposite anode material composed of monodispersed nickel phosphide (Ni 2 P) nanocrystals in situ grown into three dimensional reduced graphene oxide (RGO) matrix has been fabricated through a "heating-up" synthesis method. With an average size of 5 nm, the Ni 2 P nanocrystals are wrapped within the interior as well as on the surface of the curling RGO matrix without aggregation. In this nanostructure, RGO has excellent conductivity and an interconnected porous network, enabling the Ni 2 P/RGO nanocomposites to provide ways for rapid electron transfer and lithium ion transport. Meanwhile, due to the small size and monodispersed phase of the Ni 2 P nanocrystals, it can adapt to the volume change during charging/discharging processes. As a result, the excellent lithium-storage performance has been shown by Ni 2 P/RGO nanocomposites, concerning a long-life cycling stability (389.9 mAh g−1 after 1000 cycles at 1 C) and a high rate capability (197.7 mAh g−1 at 50 C). [ABSTRACT FROM AUTHOR]