Lithium-Ion Battery Cathodes Coated with Ultra-Thin Conductive Films for Long Cycle Life

Atomic layer deposition (ALD), as a thin film deposition technique, has been explored as a viable path to improve the performance of lithium-ion batteries. 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 breakthrough to overcome this trade-off by coating an ultra-thin conformal conductive film by ALD on the surfaces of LiMn 2 O 4 particles. The particles coated with optimized film thickness exhibit a significant improvement in capacity and cycling performance compared to uncoated and insulating ALD film (e.g., Al 2 O 3 and ZrO 2 ) coated samples both at room temperature and 55 °C for long cycling numbers.