The Influence of Zno-Modified Biomass Carbon Doping and Supporting Layered Double Hydroxides on Electrochemical Performance

Abstract

Electric energy storage devices are of indispensable importance in constructing hybrid energy storage systems. Supercapacitors are very advantageous power-type energy storage devices. With the development of electronic devices, supercapacitors also need to develop new types of flexible, lightweight electrode materials with simple preparation methods. In this article, the layered double hydroxide (LDH) with excellent electrochemical performance is introduced into the carbon nanofiber film by a simple coating method. Carbon nanofibers provide a flexible self-supporting substrate for the electrode. In addition, biomass carbon spheres modified by ZnO were also added to disperse and support the layered double hydroxides (NCNF/BC@ZO/NiCo-LDH), thus solving the problems of easy agglomeration and poor electrical conductivity of LDH. The specific capacity of the electrode reaches 697 F g−1, and 80.7% of the capacity is still retained after 10,000 cycles of charging and discharging. With the cooperation of the NCNF/BC@ZO/NiCo-LDH and NCNF, a flexible asymmetric supercapacitor is constructed. The energy density of the supercapacitor is 21 Wh kg−1 (757.1 W kg−1) and the capacity retention rate reaches 80% after 8,000 cycles. The materials used in this method are environmentally friendly, the preparation method is simple, and the raw materials are easily available. It is a scalable method for large-area production of flexible electrodes.

Keywords: carbon nanofiber, modified biochar, Ni, Co-layered double hydroxides, electrospinning, flexible supercapacitor