Atomic Layer Deposition Titanium Oxide Coating for C-Rate Improvement of Li-Ion Cathodes

Today, lithium-ion batteries (LIBs) are the most widespread technology for electric energy storage. However, the technology requires further improvement, and one of the directions is atomic layer deposition protective coating creation on LIBs electrodes. The titanium oxide thin film's influence on the NCM111 cathode electrochemical characteristics as a function of coating synthesis temperature and thickness was studied. Separately, the Solef5130 binder heat treatment effect was studied using thermogravimetry with differential scanning calorimetry. The presence of titanium and its crystallinity degree on the cathode surface were confirmed by X-ray photoelectron spectroscopy, scanning electron microscopy with energy dispersive spectroscopy, and Raman spectroscopy. Cathode C-rates were studied depending on discharge current, voltage and the number of charge-discharge cycles. Cyclic voltammetry and impedance spectroscopy were used to analyze the possible additional electrochemical reactions and coating influence on the resistance. As a result, cathodes with atomic layer deposition titanium oxide layers demonstrate cyclic stability and increased capacity retention (up to about 20%) with increasing discharge current (1C), and the coating synthesis temperature on the cathode surface plays a significant role in the final batteries capacity performance.