[en] Highlights: • SEM and TEM images present a uniformly distributed nanosize of 20–200 nm. • The results indicate that this material possesses high discharge capacity and quite good cycling stability. • The initial discharge specific capacity is 251.9 mAh g⁻¹ at 1 C (250 mA g⁻¹). • It delivers 107.5 mAh g⁻¹ for the first cycle and remains 82.7 mAh g⁻¹ after 500 cycles at 10 C. -- Abstract: High-capacity Li[Li_0.2Mn_0.54Ni_0.13Co_0.13]O₂ has been successfully synthesized as a cathode material for Li-ion battery by hydrothermal method. The prepared materials are characterized by XRD, SEM, TEM, EDS, XPS and electrochemical measurements. The XRD result shows that Li[Li_0.2Mn_0.54Ni_0.13Co_0.13]O₂ material formed a pure phase. SEM and TEM images present a uniformly distributed nanosize of 20–200 nm. The results of CV, charge–discharge tests indicate that this material possesses high discharge capacity and quite good cycling stability. It delivers 251.9 mAh g⁻¹ and 107.5 mAh g⁻¹ for the first cycle and remains 139.4 mAh g⁻¹ and 82.7 mAh g⁻¹ after 500 cycles, respectively, corresponding to 1 C and 10 C

[en] The sol-freeze-drying method is successfully applied to tune the structure of Co-free Li-rich Mn-based layered material (Li_1.2Mn_0.6Ni_0.2O₂). The structure, morphology and electrochemical performances of the tuned materials are compared with its counterpart prepared by traditional sol-gel method. The results confirm that sol-freeze-drying method is an effective approach to homogenize the transition metal distribution in Li_1.2Mn_0.6Ni_0.2O₂ without surface segregation of Ni. The specific capacity of Li_1.2Mn_0.6Ni_0.2O₂ synthesized by sol-free-drying method is 232 mAh g⁻¹ after 100 cycles at 0.2C with 96% of initial discharge capacity retained. It is much higher than the 182 mAh g⁻¹ of Li_1.2Mn_0.6Ni_0.2O₂ prepared by sol-gel method with poor capacity retention of 79%. Li_1.2Mn_0.6Ni_0.2O₂ synthesized by sol-free-drying method delivers the capacities of 252, 220, 192, 148, and 84 mAh g⁻¹ at rates of 0.1C, 0.5C, 1C, 2C, and 5C, respectively. Besides, impedance spectroscopy shows that the charge-transfer resistance of Li_1.2Mn_0.6Ni_0.2O₂ synthesized by sol-free-drying method after 20 cycles increases from 43 Ω to 51 Ω, which is much lower than that of Li_1.2Mn_0.6Ni_0.2O₂ prepared by sol-gel method from 42 Ω to 78 Ω.

[en] Highlights: • The Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ hollow microspheres have been successfully fabricated by a facile solvothermal method. • The as-prepared Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ microspheres show excellent uniformity and monodispersity. • The Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ hollow microspheres exhibit superior electrochemical performance with enhanced kinetics properties. - Abstract: Here, we designed a facile solvothermal method to prepare Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ hollow microspheres with considerable uniformity and monodispersity. In this method, lithium ions and transition metal carbonate have been simultaneously precipitated in the ethanol-polyethylene glycol mixed solvent system to form carbonate precursors, which subsequently transform into self-assembled hollow microspheres by a heat treatment. As cathode material for lithium ion batteries, its unique structure makes for sufficient contact between electrode and electrolyte to provide more reaction sites and shorter paths for Li⁺ transportation, contributing to remarkable cycling stability and excellent rate capability with improved electrochemical kinetics properties. Specifically, Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ hollow microspheres achieve a high initial discharge capacity of 287 mAh g⁻¹ at 0.1 C and 234 mAh g⁻¹ at 1 C, with capacity retentions of 85.7% and 81.3% after 100 cycles, respectively. Besides, it exhibits a high rate capacity of 150 mAh g⁻¹ even at 5 C. Moreover, the present synthesis method could also provide an effective and promising strategy for the preparation of high energy density cathode materials for lithium ion batteries.

[en] We report a delicate design and controllable preparation of Li₄Ti₅O₁₂/TiO₂/Carbon (LTO-T/C) spherical heterostructure and its application as anode for Lithium Ion Batteries (LIBs). The as-prepared self-assembled LTO-T/C spheres exhibit a chrysanthemum-like structure with abundant nanowires on the surface, which provide a large specific surface area and many transmission channels for electrons and ions transport. The carbon layer around the sphere could further increase the conductivity of the sample. As expected, the tailored LTO-T/C electrode shows excellent rate performance and outstanding reversible capacity of 220 mAh g⁻¹ and 125 mAh g⁻¹ after 500 cycles at the current density of 1.0 A g⁻¹ and 10 A g⁻¹, respectively. The improved cyclic and rate performance are attributed to its unique heterostructure and self-assembled microsphere morphology. (paper)