Rational design of MnCo2O4@NC@MnO2 three-layered core–shell octahedron for high-rate and long-life lithium storage

Abstract

With the depletion of fossil energy and rapid development of electronic equipment, the commercial lithium-ion batteries (LIBs) do not meet the current energy demand. There is an urgent need to develop novel LIBs with high capacity, long life, and low cost. In this work, we design and synthesize a MnCo₂O₄@NC@MnO₂ three-layered core–shell octahedron with good electrochemical performance using binary transition metal oxide (MnCo₂O₄), N-doped carbon (NC), and high-capacity manganese oxide (MnO₂). The three-layered structure is effective in relieving the volume expansion, improving the electronic conductivity, and strengthening the structural stability. The MnCo₂O₄@NC@MnO₂ three-layered core–shell octahedron displays a high discharge capacity of 894 mA h g⁻¹ at a current density of 500 mA g⁻¹ after 120 cycles. Even at a high current density of 1000 mA g⁻¹, the discharge capacity remains at 839 mA h g⁻¹ after 600 cycles. Furthermore, this material possesses pretty good rate performance. All the results show that this ternary composite is a good anode alternative for lithium storage.