Going Nano with Confined Effects to Construct Pomegranate-like Cathode for High-Energy and High-Power Lithium-Ion Batteries.

Abstract

Pomegranate-like Li3V2(PO4)3@C (LVP@C) cathode materials are fabricated through confined effect helped by the vacuum-assisted capillary action. The performance of LixV2(PO4)3 (x = 0-5) at an extended working voltage of 1.2-4.8 V has been studied by operando X-ray powder diffraction and hybrid functional density functional theory (DFT) calculation. The DFT calculation results suggest that Li3V2(PO4)3 can be intercalated with another two Li+ with a stable crystalline structure, which improves the specific capacity of LVP significantly. The cathode exhibits a specific capacity of 320 mAh g-1 with an energy density of 736 Wh kg-1, which is one of the best performances for intercalation cathode materials for Li-ion batteries to our knowledge. Besides, the cathode showed excellent rate capability. In the working potential of 3.0-4.8 V, it exhibits a high specific capacity of 195 mAh g-1 at 0.2 C, and even at a high rate of 30 C, it still delivers the specific capacity of 145 mAh g-1 with a power density of 15.93 kW kg-1. The good performance is mainly attributed to the unique pomegranate structure, which can provide continuous three-dimensional conductive networks for fast electron and Li-ion transfer. This paper provides a new strategy for synthesizing other cathode or anode materials with high energy and power density.