Cotton stalk-derived carbon fiber@Ni-Al layered double hydroxide nanosheets with improved performances for supercapacitors

Abstract

With the growing demands for energy storage, it is urgent to develop high-performance supercapacitors through a cost-effective and sustainable strategy. Herein, the pseudocapacitive performances of Ni-Al-layered double hydroxide (LDH) nanosheets are significantly improved after introducing carbon fibers (CFs) as the conductive matrix, which can not only prevent aggregation of Ni-Al-LDH nanosheets but also enhance the electrical conductivity of the nanocomposite. The CFs are derived from cotton stalks, which are a common agricultural waste, therefore turning waste to treasure. The obtained CF@Ni-Al-LDH exhibits high specific capacitance (1214.9 F g−1 at 1 A g−1), great rate capability (917.0 F g−1 at 10 A g−1), and good cyclability (528 F g−1 after 1000 cycles at 20 A g−1). Using this nanocomposite as the cathode material, an aqueous asymmetric supercapacitor (ASC) is assembled, and delivers acceptable specific energy of 20.1 Wh kg−1 at 932 W kg−1. The fabrication strategy in this report manifests great potential for developing next-generation pseudocapacitive materials.