Promoted Electrochemical Performance of β-MnO2 through Surface Engineering.

Different crystal facets with different surface atomic configurations and physical/chemical properties will have distinct electrochemical performances during their surface/near-surface redox reactions, and it is important to realize the controllable synthesis of high active surfaces for electrode materials. Herein, using first-principles calculations, the electrochemical performances of different surfaces of β-MnO2 were investigated. Higher surface adsorption pseudocapacitance and lower ion diffusion barrier from the surface to the near surface make the {001} surface of β-MnO2 superior to other surfaces when acting as an electrode material. Moreover, β-MnO2 with a large percentage of the {001} surface was predicted to be obtained through surface F-termination. F-termination decreases the surface energy of the {001} surface while suppressing the growth of {110} surface, which demonstrated as the surface with a much lower electrochemical performance. This work might provide a feasible strategy to synthesize anticipated surfaces with a high electrochemical performance for transition metal oxides.