One-time sintering process to synthesize ZrO2-coated LiMn2O4 materials for lithium-ion batteries

K-doped Li2ZnTi3O8/C as an efficient anode material with high performance for Li-ion batteries

Li₂ZnTi₃O₈/C and Li_1.9K_0.1ZnTi₃O₈/C were successfully synthesized using the sol–gel method. Doping K apparently yielded a wider tunnel, helpful for increasing the rate of transport of lithium ions, and furthermore yielded excellent electrochemical properties. The first discharge capacity for Li_1.9K_0.1ZnTi₃O₈/C was 352.9 mA h g⁻¹ at a current density of 200 mA g⁻¹. Li_1.9K_0.1ZnTi₃O₈/C also performed stably, retaining a capacity of 323.7 mA h g⁻¹ at the 100th cycle, indicative of its excellent cycling properties. In the rate performance test, Li_1.9K_0.1ZnTi₃O₈/C showed at the first cycle a high discharge capacity of 379.5 mA h g⁻¹ for a current density of 50 mA g⁻¹ and a capacity of 258.9 mA h g⁻¹ at 1000 mA g⁻¹. The results indicated that K-doping should be considered a useful method for improving electrochemical performances.

(A and B) CV curves of (A) Li₂ZnTi₃O₈/C and (B) Li_1.9K_0.1ZnTi₃O₈/C, (C) Initial charge–discharge curves and (D) cycling capacity and (E) rate performances of Li₂ZnTi₃O₈/C and Li_1.9K_0.1ZnTi₃O₈/C. (F) The composition of the CR2032 cell.

Nb-doped and Al2O3 + B2O3-coated granular secondary LiMn2O4 particles as cathode materials for lithium-ion batteries

In this work, to improve the cyclability and high-temperature performance of cubic spinel LiMn₂O₄ (LMO) as cathode materials, Nb⁵⁺-doped LiMn₂O₄ powders coated and uncoated with Al₂O₃ and/or B₂O₃ were synthesized via the modified solid-state reaction method. It was found that Nb⁵⁺-doped and B₂O₃ + Al₂O₃-coated LMO powders comprising 5 μm granular agglomerated fine primary particles smaller than 350 nm in diameter exhibited superior electrochemical properties with initial discharge capacity of 101.68 mA h g^-1; we also observed capacity retention of 96.31% after 300 cycles at room temperature (RT) and that of 98% after 50 cycles at 55 °C and 1C rate.