Self-supported Li4Ti5O12 nanobelt array anode with long-life and improved low-temperature performance for flexible lithium-ion batteries

Abstract

A novel self-supported Li4Ti5O12 nanobelt (LTONB) array is fabricated on the titanium foil by hydrothermal process and subsequent ion exchange. The nanobelts consist of thin nanoflakes and possess high surface area, and the addition of NaF induces a more controllable growth process. Typically, the self-supported Li4Ti5O12 nanobelt array on Ti substrate (LTONB@Ti) with an array height of 7 μm and a specific surface area of 139.1 m2 g−1 exhibits much enhanced specific area capacity, excellent cycling and low temperature performance as a LIB anode. At room temperature, it delivers a discharge areal capacity of 0.293 mAh cm−2 at 0.1 mA cm−2. After 1000 cycles at 1 mA cm−2, the capacity retention rate reaches 92.7%. The LTONB@Ti electrode also displays good low-temperature adaptability and can retain 60% room temperature-capacity even under −30 °C. It delivers a capacity of 0.138 mAh cm−2 at −20 °C (1 mA cm−2) with a stable discharge platform voltage of 1.32 V, and the corresponding capacity retention rate reaches 95.65% after 100 cycles. This is very promising for future potential application in high performance flexible energy storage devices operating over a wide temperature range.