The composite markedly improves electrochemical properties through the Ni-Mn LDO possessing good pseudocapacity and 3D GOS has better electrical conductivity.

The interconnected 3D GOS macropores reduce the diffusion distances from the external electrolyte to the interior surfaces, improve conductivity, and enable a fast reversible Faradaic reaction.

The structure obviously alleviates the reunion of LDO and the graphene layer of GOS, which can enhance the specific surface area. In addition, the carbon-based material can protect the electrodes to improve stability.

The hierarchical configuration of nanowalls consisting of numerous nanosheet structures offers a short ion diffusion path with small resistance.

All of these advantages allow the synergistic effects of LDO and 3D carbon materials.