Enhancing the Cycling Stability of Tin Sulfide Anodes for Lithium Ion Battery by Titanium Oxide Atomic Layer Deposition

Abstract

The poor cyclability problem of SnS2 anodes in Li-ion batteries (LIB) is tackled for the first time by surface coatings with TiO2 via atomic layer deposition (ALD). ALD is capable to achieve uniform, conformal nanoscale coatings onto entire SnS2 electrodes, and enhance their cycling stability and rate performance. From our study, we found that the bare electrode delivers capacities eventually down to 219.2 mA h g−1 over 50 cycles, while the ALD TiO2-coated gains a final capacity of 323.7 mA h g−1 (47.7% higher). Electrochemical impedance analyses reveal that the improvement is ascribed to the smaller charge transfer resistance and formation of thinner solid–electrolyte interfaces (SEI) in the coated electrode, thanks to its better structural integrity and less electrolyte decomposition in the presence of protective coatings.