Construction of CeO2@CoMoO4 hydrangea flower-like architectures: Insights into faradaic-dominated intercalation pseudocapacitance and high energy density supercapacitor using bio-mass derived porous carbon anode

초록

The intrinsic low energy density of supercapacitors poses a significant barrier to their widespread acceptance and large-scale production. Therefore, multiple characteristics engendered into a single material have become the current research interest. Herein, we have developed a highly porous hydrangea flower-like CoMoO4 (CMO) featuring rich cationic vacancies and successfully embedded with CeO2 nanoparticles of different concentrations (10, 25 and 50 mM) via a facile two-step solvothermal strategy, labelled as CMCO-10, CMCO-25 and CMCO-50, respectively. The incorporation of CeO2 nanoparticles significantly improved the structural, morphological and surface characteristics. However, the distinctive 2D flakes-like units with many voids and pores that make up the optimized and hierarchical structure of CMCO-25 enable quick ion intercalation/deintercalation, followed by the faradaic redox reactions to encourage intercalation pseudocapacitance. Excellent electrochemical activity is facilitated by the numerous oxidation states of the multiple metal ions. Thus, the CMCO-25 cathode manifested an impressive specific capacitance of 1402.3 F g-1 at 1.0 A g-1, outperforming the other electrodes. Furthermore, we devised an asymmetric supercapacitor (ASC) using CMCO-25 cathode assembled with bamboo leaves-derived porous carbon (BLPC) anode operated in a potential window of 1.8 V. The device yielded a remarkable energy density of 129.88 Wh kg-1 at a power density of 1961.16 W kg-1 and delivered 96.97 Wh kg-1 even at a high-power density of 12,214.84 W kg-1. Therefore, this study delineates a viable strategy to develop composite electrode materials with vacancy engineering and novel charge storage mechanism for asymmetric super-capacitors with elevated energy densities.

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