Efficient Charging of Lithium–Sulfur Batteries by Triboelectric Nanogenerator Based on Pulse Current

Abstract The pulsed output current of triboelectric nanogenerators (TENGs) has been used to charge the secondary battery recently. For a robust TENG with constant impetus, the output current will keep steady unless the external load resistance is changed. Therefore, the difference of charging current reflects the different charging resistance of the battery. Herein, the lithium–sulfur (Li–S) battery is charged by robust stable scale‐like structured TENG (SL‐TENG), and the real‐time charging current is recorded. The charging current increases with the initial potential rise, reflecting the oxidation process of the precipitated Li₂S and Li₂S₂ with poor conductivity. Then the charging current keeps almost no change in flat charge plateau, accompanying with the main production of S₈ ²⁻, S₇ ²⁻, S₆ ²⁻, and S₅ ²⁻. Finally it shows a steep drop when the potential exceeds 2.4 V, accompanying with the second oxidation stage of the main production of S₈. Moreover, under SL‐TENG charging protocol, the capacity of Li–S battery increases obviously, and Li ions tend to deposit as large grain with smooth surface. SL‐TENG charging protocol is beneficial to improve the performance of Li–S battery, as well as helping to understand the charging mechanism to some extent.