摘要
Lithium-ion capacitors(LICs) of achieving high power and energy density have garnered significant attention. However, the kinetics unbalance between anode and cathode can impede the application of LICs. Vanadium nitride(VN) with a high theoretical specific capacity(~ 1200 m Ah·g^(-1)) is a better pseudocapacitive anode to match the response of cathode in LICs. However, the insertion/extraction of Li-ions in VN's operation results in significant volume expansion. Herein, the VN/N-r GO-5composite that three-dimentional(3D) dicyandiamidederived-carbon(DDC) tightly wrapped VN quantum dots(VN QDTs) on two-dimentional(2D) reduced graphene oxid(r GO) was prepared by a facile strategy. The VN QDTs can reduce ion diffusion length and improve charge transfer kinetics. The 2D r GO as a template provides support for nanoparticle dispersion and improves electrical conductivity. The 3D DDC tightly encapsulated with VN QDTs mitigates agglomeration of VN particles as well as volume expansion. Correspondingly, the LICs with VN/Nr GO-5 composite as anode and activated carbon(AC) as cathode were fabricated, which exhibits a high energy density and power density. Such strategy provides a perspective for improving the electrochemical properties of LIC anode materials by suppressing volume expansion and enhancing conductivity.
基金
financially supported by the National Natural Science Foundation of China (Nos.22005167 and 21905152)
Shandong Provincial Natural Science Foundation of China (Nos.ZR2020QB125, ZR2020MB045 and ZR2022QE003)
China Postdoctoral Science Foundation (Nos.2021M693256, 2021T140687 and 2022M713249)
Qingdao Postdoctoral Applied Research Project, Taishan Scholar Project of Shandong Province of China (No.tsqn202211160)
the Youth Innovation Team Project for Talent Introduction and Cultivation in Universities of Shandong Province。