Layer-by-layer nanohybrids of Ni-Cr-LDH intercalated with 0D polyoxotungstate for highly efficient hybrid supercapacitor.

The layer-by-layer mesoporous nanohybrids of Ni-Cr-layered double hydroxide (Ni-Cr-LDH) and polyoxotungstate nanoclusters (Ni-Cr-LDH-POW) are prepared via exfoliation reassembling strategy. The intercalative hybridization of Ni-Cr-LDH with POW nanoclusters leads to forming a layer-by-layer stacking framework with significant expansion of the interplanar spacing and surface area. The aqueous hybrid supercapacitor (AHSC) and all-solid-state hybrid supercapacitor (SSHSC) devices are fabricated using Ni-Cr-LDH-POW nanohybrid as a cathode and reduced graphene oxide (rGO) as an anode material. Notably, the NCW-2//rGO AHSC device delivers an ED of 43 Wh kg at PD of 1.33 kW kg and excellent electrochemical stability over 10,000 charge-discharge cycles. Moreover, NCW-2//rGO SSHSC exhibits an ED of 34 Wh kg at PD of 1.32 kW kg with capacitance retention of 86% after 10,000 cycles. These results highlight the excellent electrochemical functionality and advantages of the Ni-Cr-LDH-POW nanohybrids as a cathode for hybrid supercapacitors.