“Zero-Strain” Li2VSiO5 for High-Performance Lithium Storage

Abstract

High-performance electrode materials are very important for the wide applications of lithium-ion batteries (LIBs), especially in extreme environments. Herein, electronic-conductive Li2VSiO5 microparticles with a carbon coating are developed as a new anode material with high performance in a wide temperature range. In the crystal structure of Li2VSiO5, electrochemical inactive SiO4–LiO6 polyhedron chains/layers fully surround active VO6 octahedron chains/layers, thereby accommodating the volume changes from not only Li+ insertion/extraction but also V-ion reduction/oxidation. Consequently, “zero-strain” behavior with tiny unit-cell-volume variations (maximum 0.194%) is achieved, which enables excellent cyclability with 102.8% capacity retention at 3000 mA g–1 after 3000 cycles within a safe potential range of 0.2–3.0 V. The abundant and wide channels in this special crystal structure allow fast Li+ diffusivity, significantly contributing to a large reversible capacity of 377 mAh g–1 at 50 mA g–1 and high rate capability with a 3000 vs 50 mA g–1 capacity percentage of 45.7%. At an elevated temperature of 60 °C, the excellent cyclability and safety are well retained, while the rate capability and capacity are desirably improved. Thus, this Li2VSiO5 material has great practicability for high-performance LIBs.