Homogeneous deposition of Ni(OH)2 onto cellulose-derived carbon aerogels for low-cost energy storage electrodes

Abstract

Nano-architectured carbon aerogel/Ni(OH)₂ composites have been prepared via a wet chemical approach that combines the sol–gel preparation of a highly porous carbon aerogel using microcrystalline cellulose, a low-cost and renewable polymer, as the carbon source and subsequent homogeneous deposition of Ni(OH)₂ nanoparticles onto the backbone of the carbon aerogel via a two-step chemical precipitation process. The deposited Ni(OH)₂ has small particle size (3–10 nm) and uniform dispersion and is well exposed to the electrolyte. The resulting composite possesses an interconnected, three-dimensional, high-surface-area (327 m² g⁻¹) nanostructure, which provides efficient transport of electrolyte ions and electrons and enables a fuller utilization of Ni(OH)₂, thus leading to excellent electrochemical performance. The composite electrode exhibits high specific capacitance of 1906 and 1206 F g⁻¹ at current density of 1 and 20 A g⁻¹, respectively, which are much higher than those of Ni(OH)₂. Moreover 89% capacitance is retained after 4000 cycles, implying a good cycling stability.