Scalable fabrication of quantum-sized CoS1.97 nanoparticles anchoring on biomass carbon aerogel for energy storage application

Abstract

Exploiting earth-abundant and cost-efficient electrode materials is an effective strategy to fulfil the urgent demand for high-efficiency energy-storage. Carbon aerogels (CAs) with conductive skeleton and large specific area have attracted significant attention in electrode materials. However, how to achieve the large-scale production of CAs with both high energy storage capability and reasonable cost still remains a challenge. Herein, a scalable and cost-effective route toward constructing cobalt sulfide nanoparticles/carbon aerogel (CoS1.97/CA) hybrid electrode is described. Quantum-sized CoS1.97 nanoparticles are synthesized by in situ selective vulcanization of Co2+ absorbed on the carbonaceous watermelon tissues which acts as current collector for the fast electrons transfer. Quantum-sized CoS1.97 nanoparticles provide abundant active sites for the redox reaction with electrolyte ions in the hybrid electrode, thus leading to an excellent electrochemical capacity of 1715 C g−1. Furthermore, an asymmetric supercapacitor is assembled by employing CoS1.97/CA-500 as positive electrode and CA as negative electrode, which delivers the highest capacity of 51.5 mAh g−1 and energy density of 36.4 Wh kg−1. In addition, an impressive cycling span of 20000 cycles is obtained with capacity retention reaching up to 98.9%, demonstrating its high stability for real-world application. These findings demonstrate the bio-inspired and cost-effective development of 3D carbon aerogel electrode for incorporating with other novel materials for the applications in energy storage.