Influence of Cu2+ doping concentration on the catalytic activity of CuxCo3−xO4 for rechargeable Li–O2 batteries

Abstract

The electrochemical performance of rechargeable lithium–oxygen (Li–O₂) batteries relies on the catalysts used in the cathode to a great extent. Herein, a series of Cu_xCo_3−xO₄ nanorods with different Cu²⁺ concentrations was prepared by a convenient hydrothermal method. The corresponding structures and electrochemistries were further characterized in order to reveal the composition effect of catalyst on catalytic activity. Experimental characterization and theoretical calculations indicate that more Cu²⁺ occupying Co²⁺ positions and dispersing on the catalyst surface has an enhanced catalytic activity in terms of higher capacity, lower overpotential and better reversibility. This implies that suitable charge transfer from Li₂O₂ to the catalyst plays an important role in improving the electrochemical performance of Li–O₂ batteries. The present study is helpful for designing a highly active catalyst by tuning the composition of the catalyst surface.