Dual-MnCo₂O₄/Ni electrode with three-level hierarchy for high-performance electrochemical energy storage

The design of micro/nanostructures with high porosity is very important to achieve reliable and high-performance capacitive materials for electrochemical energy storage. The complexity of this strategy is limited by the lack of a facile method to synthesize multi-hierarchical architectures with both high electroactive surface area and fast ion diffusion ability. Here, we report a designed MnCo₂O₄/Ni electrode with multilevel hierarchy containing mesoporous MnCo₂O₄ nanosheet layers and vertically aligned MnCo₂O₄ nanoflake layers on a macroporous Ni foam support (∼500 μm). The dual-MnCo₂O₄ layers are well connected with each other and grown directly on the Ni foam support. As a result, the obtained dual-MnCo₂O₄/Ni electrode delivers an excellent specific capacity up to 283 mAh g⁻¹ and long-term performance stability over 2000 cycles.