Integrated Li3VO4 and boron doped carbon microspheres with high tap density for high-rate and durable lithium storage

Abstract

As an essential representative of novel anode materials with high capacity and safe voltage, Li3VO4 (LVO) still suffers from the challenges of low electronic conductivity and low tap density of nanostructures. Herein, a strategy of nanoization and recombination is proposed to synthesize the integrated LVO and boron doped carbon microspheres (LVO/BC-MS-550) with high tap density via a chemical crosslink method to improve the Li-ion storage performance. LVO/BC-MS-550 is consisted of the well-dispersed LVO nano-crystals in tightly stacked carbon spheres derived from the cross-linked network of boric acid (BA) and polyvinyl alcohol (PVA). By introducing conductive and continuous carbon framework, the LVO crystals are controlled to grow in the confined region with mitigated volume changes, as well as the enhanced electronic conductivity. Benefiting from the constructive advantages, LVO/BC-MS-550 anode delivers a specific capacity of 512.1 mAh g−1 at the current density of 0.2 A g−1 (0.34 C) after 300 cycles, and ultra-long cycling performance of 231.8 mAh g−1 over 5000 cycles at the charging/discharging current density of 4/2 A g−1, exhibiting rapid pseudo-capacitance reaction kinetics. This work provides valuable insights into the fabrication of in situ three-dimensional crosslinked carbon and LVO composites for alternative grid-scale electrochemical applications.