Significant Capacity Improvement and Long Cycle-Life of Lithium-Ion Battery through Thin Film Stabilized Cathode Particles

Lithium-ion batteries (LIBs) have been implemented as a high energy and high power density source in numerous electronic devices, electrical vehicles, and space-crafts. A great deal of research has been carried out to improve the lifetime and capacity of LIBs. Thin film coatings on LIB electrode powders have proven to be an effective way to improve the capacity retention, rate capability, and thermal stability of electrode materials. Atomic layer deposition (ALD), as a thin film deposition technique, has been explored as a viable path to improve the performance of LIBs. However, a trade-off between the species transport (capacity) and protection (lifetime), resulting from the insulating properties of ALD films, is the key challenge in ALD technology. Here, we report a new strategy to overcome this trade-off by coating an ultra-thin conformal conductive ALD film on the surfaces of LiMn₂O₄ particles. The optimized conductive film coated particles exhibit a significant improvement in capacity and cycling performance compared to uncoated samples at room temperature and 55 °C for long cycling numbers. The initial capacity of the conductive film coated sample shows 24% increment compared to the capacity of the uncoated one, and 96% and 95% of the initial capacity is retained after 1,000 cycles with 1 C rate at room temperature and 55 °C, respectively.