Electronic structure engineering of CaMoO4 nanoparticle-decorated mesocarbon microbeads for high-performance aqueous hybrid supercapacitors

MCMB was introduced to tune CaMoO 4 and improve its conductivity and active sites. • MCMB limits CaMoO 4 aggregation, disperses particles, and forms conductive paths. • CaMoO 4 @MCMB delivers 701.2 F g −1 and an energy density of 89.4 Wh kg −1 . Calcium molybdate (CaMoO₄) suffers from low intrinsic conductivity and insufficient active sites for ion storage. Herein, mesocarbon microbeads (MCMB) are integrated to construct a CaMoO₄@MCMB composite, where the carbon skeleton prevents nanoparticle agglomeration, ensures uniform dispersion, and builds a continuous conductive network. DFT calculations reveal interfacial electronic coupling between CaMoO 4 and MCMB, supporting the UV–Vis band-gap narrowing trend from 3.81 to 1.61 eV, indicating enhanced charge transfer. As a result, the optimized electrode delivers a specific capacitance of 1396.9 F g −1 at 0.5 A g −1 (2.73 × pristine CaMoO₄). An asymmetric device (CaMoO₄@MCMB//AC) achieves 24.8 Wh kg −1 at 374.99 W kg −1 with 87.2% retention after 5000 cycles. This work provides a carbon-coupling strategy to activate molybdate-based battery-like electrodes for hybrid energy storage. Download: Download high-res image (98KB) Download: Download full-size image