High-Capacity Li-Ion Batteries Using SiO-Si Composite Anode and Li-Rich Layered Oxide Cathode: Cell Design and Its Safety Evaluation

High-capacity Li-ion batteries were developed using the SiO-Si composite anode and lithium-rich layered oxide (LR-NMC) cathode in which the irreversible capacity of the anode can be compensated by that of the cathode rather than by conventional Li pre-doping process using lithium metal foil. The irreversible capacity of the anode could be adjusted by preparing a composite anode with the SiO and Si in which the irreversible capacity was equalized to that of the cathode at a Si/(SiO + Si) mass ratio of 0.8. The cell using the composite anode displayed a discharge capacity of 182 mAh g −1 as the cathode capacity at the 0.1C-rate, and a stable cycle performance for over 100 cycles with a discharge capacity of ca. 150 mAh g −1 at the 0.5C-rate and 30°C. The cell also displayed a stable cycle performance at 60°C the same as that at 30°C, and no drastic degradation even at 80°C. Furthermore, the cell can even be discharged at −55°C. The cell could discharge even at the 10C-rate. No thermal runaway was observed during the nail penetration test for the 1000 mAh cell. The cell can be used as the power source of a remote control quadcopter.