A scalable ternary SnO2–Co–C composite as a high initial coulombic efficiency, large capacity and long lifetime anode for lithium ion batteries

Abstract

A new ternary SnO₂–Co–C composite is produced using a facile and scalable ball milling method, which has a microstructure that includes refined SnO₂–Co hybrids embedded in graphite. The Co additives dramatically inhibit Sn coarsening in the lithiated SnO₂, which enables highly reversible conversion reactions in the SnO₂-based ternary composite during cycling. The electrodes exhibit high ICEs with an average of 80.8% and a reversible capacity of 780 mA h g⁻¹ at 0.2 A g⁻¹ after 400 cycles when the composite was manufactured via small planetary ball milling, and they achieve 875 mA h g⁻¹ after 250 cycles when the material is prepared on a large-scale with a roller mill. Even at a high rate of 2 A g⁻¹, the composite has a long lifetime and delivers 610 mA h g⁻¹ after 1000 cycles. Furthermore, a stable capacity of 410 mA h g⁻¹ can be also retained in a full cell combined with a LiFePO₄ cathode and SnO₂–Co–C anode when cycling within 2.3–3.4 V at 0.2C. The new ternary SnO₂–Co–C composite demonstrates excellent comprehensive electrochemical performances, and it is a promising candidate anode material for use in practical applications.