Construction of a LiVO3/C core–shell structure for high-rate lithium storage

Abstract

As an alternative anode material for lithium-ion batteries (LIBs), LiVO₃ has shown great potential. We wished to fully reveal its potential for lithium storage. We introduced low-cost oxalic acid as a carbon source to construct a LiVO₃/C core–shell structure. Employed as LIB anodes, the highly reversible specific capacity of LiVO₃/C reached 776.0 mA h g⁻¹ after 200 cycles at 0.2 A g⁻¹. During five periods of rate testing at various current densities (0.2, 0.5, 1.0, 2.0, 5.0 A g⁻¹), the average capacity of the LiVO₃/C electrode was 365.8 mA h g⁻¹ at 5.0 A g⁻¹, and retained a high discharge capacity of 569.0 mA h g⁻¹ when the current was returned to 0.2 A g⁻¹. Impressively, the LiVO₃/C anode presented an unprecedented high-rate long cycling performance of 205.0 mA h g⁻¹ at 10.0 A g⁻¹ after 2000 cycles. The unprecedented lithium-storage ability was attributed to the unique core–shell structure, in which all-around carbon encapsulation provided many interfaces, and enhanced the electron conductivity and structural consistency of the LiVO₃/C electrode. Moreover, the adaptive reaction dynamics of the LiVO₃/C electrode were documented. That is, the gradually increasing pseudocapacitance contribution and decreasing charge-transfer impedance upon cycling were the intrinsic drivers of the excellent rate performance. This work promotes further development of anode materials based on LiVO₃.