Nowadays, the restricted availability of fossil fuels longs for the more efficient energy storage devices. Due to the high reactivity, metal alkoxides are thought to be viable potential electrode materials for the energy storage field. In this work, the B-doped NiCo-glycerate (NiCo–B-glycerate) with sphere@nanosheet structure is obtained through a straightforward method for supercapacitors. The B doping and 2D nanosheets covering on the sphere surface have an effect on the creation of defective sites, adjustment of the electronic properties, and reduction the charge transfer distance. The NiCo–B-glycerate electrode provides an ultrahigh specific capacitance of 2036 F g⁻¹ at the current density of 1 A g⁻¹ while maintaining a good rate performance of 74.6 % at current density of 30 A g⁻¹. Moreover, an asymmetric supercapacitor is successfully assembled based on the NiCo–B-glycerate, showing a high energy density of 58.3 Wh kg⁻¹ at a power density of 0.8 kW kg⁻¹. This study might encourage the development of metal alkoxides for application in energy storage field.