Direct hydrothermal treatment of sugarcane juice for 3D oxygen-rich carbon Aerogel/NiCo2O4 based supercapacitor

Abstract

A direct hydrothermal synthesis is reported to fabricate proficient carbon aerogel via raw sugarcane juice for energy storage. Sugarcane-derived carbon aerogel (SCA) exhibiting 3D interconnected meso/microporous structure reveals enhanced interlayer spacing (3.9 Å) and large surface area (2000 m2 g−1) with low bulk density (0.10 g cm−3). High charge storage (385 F g−1 at 5 mV s−1) and rate performance (5–400 mV s−1) indicate that heteroatom(s) functionalized SCA endures good ion diffusion coefficient (D = 2.1 × 10−11 cm2 s−1). Furthermore, NiCo2O4/SCA nanocomposite is developed sonochemically wherein spinel NiCo2O4 nanoflakes are immobilized over SCA such that the basic skeleton (microporosity) and ion accessibility (D = 1.26 × 10−11 cm2 s−1) of SCA is preserved. Hierarchical deposition of NiCo2O4 over SCA affords fairly high surface area (150 m2 g−1) with specific capacitance 473 F g−1 at 5 mV s−1. The fabricated hybrid supercapacitor: SCA‖NiCo2O4/SCA displays more than twice energy as well power density (25 Wh kg−1, 6245 W kg−1) compared to symmetric cell: SCA‖SCA (10.4 Wh kg−1, 2378 W kg−1) owing to synergism of carbonaceous &pseudo components. The research entails first ever direct use of saccharide juice as carbon aerogel for supercapacitor technologies via facile synthesis without use of any toxic chemicals.