Fast and Reversible Li Ion Insertion in Carbon-Encapsulated Li3VO4 as Anode for Lithium-Ion Battery

Carbon-encapsulated Li3VO4 is synthesized by a facile environmentally benign solid-state method with organic metallic precursor VO(C5H7O2)(2) being chosen as both V and carbon sources yielding a core-shell nanostructure with lithium introduced in the subsequent annealing process. The Li3VO4 encapsulated with carbon presents exceeding rate capability (a reversible capability of 450, 340, 169, and 106 mAh g(-1) at 0.1 C, 10 C, 50 C, and 80 C, respectively) and long cyclic performance (80% capacity retention after 2000 cycles at 10 C) as an anode in lithium-ion batteries. The superior performance is derived from the structural features of the carbon-encapsulated Li3VO4 composite with oxygen vacancies in Li3VO4, which increase surface energy and could possibly serve as a nucleation center, thus facilitating phase transitions. The in situ generated carbon shell not only facilitates electron transport, but also suppresses Li3VO4 particle growth during the calcination process. The encouraging results demonstrate the significant potential of carbon encapsulated Li3VO4 for high power batteries. In addition, the simple generic synthesis method is applicable to the fabrication of a variety of electrode materials for batteries and supercapacitors with unique core-shell structure with mesoporous carbon shell.