Phosphorus controlled metal organic framework derived dual phase cobalt phosphide nanoparticles embedded in nitrogen doped carbon scaffold with multiwalled carbon nanotube-MXene for hybrid supercapacitor

Abstract

Dual-phase cobalt phosphides (CoxPy) are promising electrode materials for supercapacitor (SC) due to its superior electronic conductivity; however, surface modification is crucial to further enhance its energy density. Herein, surface-modified metal-organic framework (MOF)-derived CoxPy nanoparticles embedded in a nitrogen (N)-doped carbon on carbon cloth (CoxPy@NC/CC) are synthesized via co-precipitation and phosphidation by varying quantity of phosphorus precursor. MOF-derived electrodes offer abundant electroactive sites and a highly porous surface, which shortens charge transfer paths and mitigate volume expansion during cycling. The CoxPy@NC/CC electrode exhibited a specific capacitance (Cs) of 379.8 F g−1 at 1 mA cm−2, and retaining 92.9% of its Cs over 12,000 cycles. The quasi-solid-state hybrid SC (QSHS) device, using a positive CoxPy@NC/CC and a negative multi-walled carbon nanotubes (MWCNT)/Ti3C2TX-MXene/CC electrodes with a polymer-based electrolyte, exhibited a highest Cs of 108.9 F g−1, a specific energy of 29.7 Wh kg−1 and outstanding stability of 90.17% over 5000 cycles. This work is supported by density functional theory (DFT) simulations to obtain the adsorption energy. The achieved parameters confirm the suitability of the CoxPy@NC/CC electrode for SC application.