A highly sought multi-functional material for electrochemical energy storage and conversion devices offers a novel approach to addressing global energy concerns. We propose the stable CoNb2O6 as a novel functional electrode and catalyst for anion-intercalative energy storage and water splitting processes. The material has a spherical microstructure and evenly dispersed distribution. Electrochemical investigations clearly show that the electrode’s intercalation type pseudocapacitance makes a significant contribution. When oxygen vacancies exist, O2− ion intercalation occurs via a stable columbite structure. The CoNb2O6 electrode offers a maximum charge storage capacity of 70 Cg−1 at 1 Ag−1 and a good capacity retention of 81 % after 5000 cycles. The material’s functionality is extended to include a water splitting catalyst, electrocatalytic oxygen, and hydrogen evolution (OER/HER) processes. During our exploration of the CoNb2O6 for precious-metal-free electrocatalysts and found that this trirutile system has a good OER and acceptable HER activities. As a result, we obtained a lower OER overpotential of 450 mV at 10 mAcm−2 and a low tafel slope of 106 mV dec−1 in 1 M KOH. Furthermore, the material may electrocatalyze the hydrogen evolution reaction in basic solution, demonstrating moderate activity (
) and good stability in alkaline medium. This study demonstrates the prospective multifunctional activity of CoNb2O6 for energy storage and conversion devices.