VNQDs anchored in N-doped porous carbon with pseudocapacitive behavior for fast charge and discharge lithium-ion batteries

Vanadium nitride (VN) is an attractive anode material for lithium-ion batteries (LIBs) due to its large theoretical capacity and excellent electrical conductivity; however, its low rate performance and poor cycle life caused by slow reaction kinetics and large volume changes have limited its practical application. Herein, in situ formation of VN quantum nanodots (VNQDs) anchored on a three-dimensional porous N-doped carbon (PNC) skeleton was achieved by a simple and scalable template-assisted and heat treatment strategy to build porous VNQDs@PNC composites as pseudocapacitive anode materials for LIBs. The resulting composites provide abundant active sites (uniform distribution of VNQDs), excellent electrical conductivity (N-doped carbon) and a shortened ion di?usion channel. The pseudo-capacitive controlled behaviour accelerates the fast lithium intercalation and delithiation process. As a result, the VNQDs@PNC-3 anode materials exhibit high lithium-ion storage capacities (687.3 mAh g−1 under 100 mA g−1), excellent rate performance (239 mAh g−1 at 15 A g−1), and long-term stability (372.1 mAh g−1 at 2 A g−1 with a capacity retention of 80.06% over 3000 cycles). When coupled with a LiFePO4 (LFP) cathode, the full battery exhibits a large capacity of 63.4 mAh g−1 over 5000 cycles at 0.5 A g−1.This work further verifies the feasibility of kinetics-compatible electrode material design strategies toward high rate LIBs.