Mesoporous nanohybrids of 2-D Cobalt-Chromium layered double hydroxide and polyoxovanadate anions for high performance hybrid asymmetric supercapacitors

An exfoliation-reassembling process is utilized to develop mesoporous intercalative nanohybrids of cationic 2-D cobalt-chromium-layered double hydroxide (Co-Cr-LDH) nanosheets and polyoxovanadate (POV) anions (Co-CrLDH-POV nanohybrids). The Co-Cr-LDH-POV nanohybrid displays a maximum specific capacity (SC) of 732 C g(-1) at 1 A g(-1), attributed to the layer-by-layer porous structures with expanded gallery height. An aqueous and solid-state hybrid asymmetric supercapacitor devices are fabricated by Co-Cr-LDH-POV nanohybrid as cathode and rGO nanosheets as an anode. An aqueous hybrid asymmetric supercapacitor (AHAS) device delivers an SC of 238.72 C g(-1) at 0.8 A g(-1) with a specific energy (SE) of 53.04 Wh kg(-1) at 512 W kg(-1) specific power (SP) and capacity retention of 85% over 10,000 cycles. Moreover, a solid-state hybrid asymmetric supercapacitor (SHAS) device displays a high SC of 148 C g(-1) at 2.4 A g(-1) with a SE of 27.59 Wh kg(-1) at 2560 W kg(-1) SP and capacity retention of 90.23% over 5000 cycles. Nevertheless, the obtained results suggest that such a new type of porous LDH-polyoxometalate (LDH-POM) based nanohybrids are useful as cathode for next-generation energy storage applications.

Automated summary

An exfoliation-reassembling process was used to develop mesoporous intercalative nanohybrids of cationic 2-D cobalt-chromium-layered double hydroxide nanosheets and polyoxovanadate anions, which exhibited promising performance in asymmetric supercapacitors devices.