With the growing demands for energy storage, it is urgent to develop high-performance supercapacitors through a cog-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 conducive 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 (528F 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.