Cobalt substitution-induced π-donation in NiMoO4 for enhanced electrochemical charge storage.

ABSTRACT

NiMoO4 (NM) has garnered significant attention due to its rich d-orbital electronic structure and multivalent electroactive cations. However, the inherently low electrical conductivity of NM limits its reaction kinetics. Herein, cobalt-substituted NM (Co-NM) nanorods were prepared via a hydrothermal reaction followed by subsequent thermal treatment. The incorporation of Ni-O-Co configurations stimulates an enhanced π-donation effect of the Co-O bond, facilitating the hybridization between the O 2p and Co 3d orbitals and thereby boosting charge transfer kinetics during electrochemical processes. The optimized 10 %Co-NM nanorods demonstrated a remarkable specific capacity of 557.8 C·g-1 at 1 A·g-1. Furthermore, an asymmetric supercapacitor constructed with 10 %Co-NM as the positive electrode and FeOOH as the negative electrode, achieved a significant energy density of 63.58 Wh·kg-1 at a power density of 805.38 W·kg-1. Thus, our work provides new insights into the rational design of stable bridging configurations to significantly improve electrochemical reaction kinetics.