Ultra-small bimetallic CoNi nanoalloy decorated on 2D g-C3N4 enables high performance and long durability for asymmetric supercapacitor

Abstract

Alloying metals change their characteristics significantly. Nanoalloy electrodes are excellent materials for pseudocapacitors, which bridge supercapacitors and batteries. We report an ultra-small bimetallic CoNi nanoalloy functionalized on 2D graphitic nitride (g-C3N4) sheets via hydrogenation. An asymmetric supercapacitor of CoNi@g-C3N4 nanoalloy fabricated with activated carbon nanofiber (ACF) shows a wide potential window of 1.5 V and an excellent life span of 8000 cycles at an ultra-high current density of 15 A g−1. Further, we operated the cell at 2 °C, RT, 50 °C and 65 °C, which shows an enhanced energy density of 26 Wh kg−1 at 50 °C than at a lower temperature (2 °C) of 15 Wh kg−1.