Novel Skutterudite CoP3 -Based Asymmetric Supercapacitor with Super High Energy Density.

Skutterudite CoP3 holds a unique structural formation that exhibits much better electronic properties for obtaining high energy density supercapacitors. Herein, novel skutterudite Ni-CoP3 nanosheets are constructed by etching and coprecipitating at room temperature and subsequent low-temperature phosphorization reaction. Benefiting from the enhanced electrical conductivity and more electroactive sites brought about by adjusting the electronic structure with Ni incorporating the Ni-CoP3 electrode with a battery-type demonstrates an ultrahigh specific capacity of 0.7 mA h cm-2 and exceptional cycling stability. The asymmetric supercapacitor (ASC) device fabricated by employing Ni-CoP3 and activated carbon (AC) as positive and negative electrodes, resepectively, exhibits a remarkable high energy density of 89.6 Wh kg-1 at 796 W kg-1 and excellent stability of 93% after 10 000 cycles, due to the skutterudite structure. The skutterudite Ni-CoP3 shows a great potential to be an excellent next-generation electrode candidate for supercapacitors and other energy storage devices.