Abstract
In order to solve the contradiction between the rapidly growing energy demand and the excessive ex-ploitation of fossil fuels,it is urgent to research and develops more environmentally friendly and efficient energy storage technologies.Therefore,the development of high-performance cathode materials to en-hance the energy density of SIB is currently one of the most important topics of scientific research.Ad-vanced high-voltage and low-cost cathode material for SIBs,a composite of carbon-coated Na4MnCr(PO4)3(NASICON-type),polyvinylpyrrolidone(PVP),and modified carbon nanotubes(CNTs)is prepared by sol-gel and freeze-drying method.Due to the high conductivity of CNTs,the conductivity of the compos-ite is significantly improved,and its initial capacity is increased to 114 mAh/g at 0.5 C and 96 mAh/g at 5 C(Mn2+/Mn4+conversion for voltage windows 1.4-4.3 V).Moreover,the multi-electrons transfer of Cr3+/Cr4+and Mn2+/Mn4+can provide a high capacity of 165 mAh/g at 0.1 C and 102 mAh/g at 5 C in the high voltage window of 1.4-4.6 V.Furthermore,PVP can effectively inhibit the Jahn-Teller effect caused by Mn ion,making the composite have more excellent high-rate performance and stabil-ity.In addition,GITT,EIS and CV curves were drawn to better reveal the excellent kinetic properties of Na4MnCr(PO4)3@C@PVP@CNT cathode,and the mechanism of its performance improvement is deeply studied and discussed.Accordingly,the co-doping of CNTs and PVP is a simple way to high conductivity and fast charging of cathode materials for SIBs.
万方数据