Investigation of Li5Cr7Ti6O25 as novel anode material for high-power lithium-ion batteries

In this work, Li₅Cr₇Ti₆O₂₅ as a new anode material for rechargeable batteries is fabricated through a simple sol-gel method at different calcination temperatures. The X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, charge/discharge curve and cyclic voltammograms are utilized to study the crystal structures, morphologies and electrochemical properties of as-obtained Li₅Cr₇Ti₆O₂₅ samples. The impact of calcination temperatures on morphologies and electrochemical properties of Li₅Cr₇Ti₆O₂₅ is discussed in detail. The test result shows that the 800 °C is a proper calcination temperature for Li₅Cr₇Ti₆O₂₅ with excellent electrochemical properties. Cycled at 200 mA g⁻¹, it displays a high initial reversible capacity of 146.6 mA h g⁻¹ and retains a considerable capacity of 130.8 mA h g⁻¹ after 300 cycles. Even cycled at large current density of 500 mA g⁻¹, the initial reversible capacity of 129.6 mA h g⁻¹ with the capacity retention of 88% after 300 cycles is achieved, which is obviously higher than that of Li₅Cr₇Ti₆O₂₅ prepared at 700 °C (80.5 mA h g⁻¹ and 68%) and 900 °C (98.4 mA h g⁻¹ and 80%). In addition, in-situ XRD analysis reveals that Li₅Cr₇Ti₆O₂₅ exhibits a reversible structural change during lithiation and delithiation processes. The above prominent electrochemical performance indicates the great potential of the Li₅Cr₇Ti₆O₂₅ obtained at 800 °C as anode material for rechargeable batteries.