Li5Cr9Ti4O24: A new anode material for lithium-ion batteries

• Capacity of Li4Ti5O12 is increased by combining Ti3+/Ti4+ and Cr2+/Cr3+ couples.
• Spinel Li5Cr9Ti4O24 with a larger theoretical capacity of 323 mAh g−1 is prepared.
• Discharge and charge capacities of Li5Cr9Ti4O24 are larger than those of Li4Ti5O12.
• Li5Cr9Ti4O24 shows a large electronic conductivity and Li+ diffusion coefficient.
• Li5Cr9Ti4O24 further exhibits an ultra-high rate performance and good cyclability.

Li4Ti5O12 suffers from its small theoretical capacity and low conductivity, limiting its practical applications in lithium-ion batteries. Although its conductivity has been improved, its theoretical capacity has not been increased so far. Here, for the first time, the capacity of Li4Ti5O12 is increased by combining Ti3+/Ti4+ and Cr2+/Cr3+ redox couples. Spinel Li5Cr9Ti4O24 with a larger theoretical capacity of 323 mAh g−1 is designed and fabricated through a facile solid-state reaction method. The as-fabricated Li5Cr9Ti4O24 delivers a large initial discharge capacity of 311 mAh g−1 between 3 and 0.001 V (vs. Li/Li+) at a current density of 62.5 mA g−1, which is larger than that of Li4Ti5O12. Furthermore, it exhibits good (electronic and ionic) conductivity and a high rate performance.

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