Ultrathin Direct Atomic Layer Deposition on Composite Electrodes for Highly Durable and Safe Li‐Ion Batteries

Abstract : In order to employ Li-ion batteries (LIBs) in next-generation hybrid electric and/or plug-in hybrid electric vehicles (HEVs and PHEVs), LIBs must satisfy many requirements: electrodes with long lifetimes (fabricated from inexpensive environmentally benign materials), stability over a wide temperature range, high energy density, and high rate capability. Establishing long-term durability while operating at realistic temperatures (5000 charge-depleting cycles, 15 year calendar life, and a range from -46 deg C to +66 deg C) for a battery that does not fail catastrophically remains a significant challenge. Recently, surface modifications of electrode materials have been explored as viable paths to improve the performance of LIBs for vehicular applications. Here we clearly demonstrate that conformal ultrathin protective coating by inactive metal oxide without disrupting inter-particle electronic pathway can be realized by atomic layer deposition (ALD) directly performed on a composite electrode, which leads to significant improvement of both long-term durability and safety of NG anode. Also ALD coatings are significantly more promising than efforts that have been previously reported.