Improvement on high-temperature electrochemical performance of lithium-ion pouch cells by spatial atomic layer deposition

To alleviate the poor cycling stability and sluggish kinetics commonly observed with the lithium-ion batteries (LIBs) assembled with Ni-rich layered cathode, natural graphite (NG) anode, and polymeric separators; in this work, a spatial atomic layer deposition (ALD) technique was developed to uniformly coat TiO2 nanolayer on the Ni-rich cathode, NG anode, and the separator. To assess the electrochemical performance of nano-coated electrodes, a pouch cell was assembled with the nominal capacity of ∼2200 mAh. The ALD-treated pouch cells were cycled extensively at 25 and 55°C. Even after high-temperature cycling, the ALD-treated cells did not demonstrate any appreciable volumetric expansion. Analyzing the microstructure of the ALD-coated electrodes revealed that the ALD coating facilitates the formation of a thin and robust solid-electrolyte interfacial layer on the anode and mitigates the metal leaching from the cathode electrode, resulting in high-rate capability and exceptional cyclic stability. The spatial ALD coating technique demonstrated in this work enables a continuous fabrication of TiO2-coated electrodes with a high production rate (1.2‒2.4 m min−1).