High-energy, fast-charging, long-life lithium-ion batteries using TiNb2O7 anodes for automotive applications

Electrochemical properties of TiNb2O7 (TNO) electrodes during lithium storage have been studied in order to develop an alternative anode with high-capacity, fast-charging, and long-life to Li4Ti5O12 (LTO) in lithium-ion batteries. High-density TNO (HD-TNO) composite electrode consisting of micro-size spherical TNO secondary particles coated with carbon exhibited high-rate capability, long cycle-life, and a high volumetric capacity of more than twice that of LTO composite anodes. Large-size lithium-ion batteries using the HD-TNO anode and a LiNi0.6Co0.2Mn0.2O2 (NCM) cathode with a capacity of 49 A h were fabricated for automotive applications, and were found to have a high energy density of 350 W h L−1, a high input-power density of 10 kW L−1 for 10 s at 50% state of charge (SOC), and fast-charging from 0% to 90% SOC in less than 6 min. The capacity retention at 7000 cycles was 86% by full charge-discharge cycling at 1C rate. Cycle life was predicted to be 14000 cycles at 80% capacity retention. It was demonstrated that the TNO/NCM batteries have high energy-density, fast-charging, and long cycle-life for automotive applications such as electric vehicles with long driving ranges by fast-charging.