Comprehensive Investigation of the Crystal Structure of Cation‐Disordered Li3VO4 as a High‐Rate Anode Material: Unveiling the Dichotomy between Order and Disorder

Abstract

AbstractThis study investigates mechanochemical synthesis and cation‐disordering mechanism of wurtzite‐type Li3VO4 (LVO), highlighting its promise as a high‐performance anode material for lithium‐ion batteries and hybrid supercapacitors. Mechanochemical treatment of pristine LVO using a high‐energy ball mill results in a “pure cation‐disordered” LVO phase, allowing for meticulous analysis of cation arrangement. The X‐ray and neutron diffraction study demonstrates progressive loss of order in LVO crystal with increasing milling duration. High‐resolution transmission electron microscopy reveals disrupted lattice fringes, indicating cationic misalignment. Pair‐distribution function analysis confirms loss of cation arrangements and the presence of short‐range order. Combination of these multiple analytical techniques achieves a comprehensive understanding of cation regularity and clearly demonstrates order/disorder dichotomy in cation‐disordered materials, ranging from short (<8 Å) to middle‐long range (8–30 Å), using an integrated superstructure model of the cation‐disordered LVO crystals. Electrochemical testing reveals that mechanochemically treated LVO exhibits superior rate capability, with a 70% capacity retention at a high current density of 50C‐rate. Lithium diffusion coefficient measurements demonstrate enhanced lithium‐ion mobility in the mechanochemically treated LVO, attributed to cation‐disordering effect. These findings provide valuable insights into mechanochemical cation‐disordering in LVO, presenting its potential as an efficient anode material for lithium‐ion–based electrochemical energy storage.