Synergetic effect of trimetallic double hydroxide nanospikes embraced N-doped graphene nanosheets as electrode material for supercapacitors

Abstract

In the energy storage sector, layered double hydroxides (LDHs) are coming to the forefront as a promising option for electrode materials. However, LDHs suffer from insufficient intrinsic conductivity and agglomeration during formation which restrict their wide applications. In this context, a two-step hydrothermal technique is employed to synthesize NiCoMn hydroxide (NCM)/N-doped graphene (NG). Initially, NG is produced through hydrothermal treatment utilizing urea to serve as both a reduction and doping source. Subsequently, a straightforward hydrothermal technique is utilized to cultivate NCM onto the surface of NG nanosheets. The electrochemical properties of NCM-NG composite with different compositions of NG have been analyzed, resulting in capacitance increment on account of increased conductivity and large number of active sites upon incorporation of NG as compared to pristine NCM. Moreover, NG nanosheets inhibit the agglomeration of NCM nanospikes. Amongst different compositions, NCM-NG-2 nanohybrid secured the highest specific capacitance (Cs) of 783.5 F/g at 0.25 A/g. The Asymmetric supercapacitor device assembled with NCM-NG-2 (anode) and activated carbon (AC) (cathode) exhibits the Cs of 114.5 F/g at 0.5 A/g. The optimized specific energy (Es) of 31.8 Wh/kg and specific power (Ps) of 473.4 W/kg with remarkable retention of 101.9 % up to 15,000 continuous cycles, indicating a higher potential of the NCM-NG-2 electrode in energy storage applications. These findings open new avenues for developing highly productive multi-material electrodes for utilization in energy storage systems.