Multifunctional zinc silicate coating layer for high-performance aqueous zinc-ion batteries

Dendrite growth during the continuous charge/discharge process is a serious problem that leads to internal short circuit in aqueous zinc-ion batteries. Herein, a multifunctional zinc silicate polymer (LSO) was proposed to address the issues. LSO can prevent direct contact between electrolyte and zinc anode, thereby suppressing the severe dendrite growth. Its mechanically stable structure of LSO can restrain the stress release to further stabilize the electrode. In addition, LSO is chemically bonded to zinc anode to ensure superior overall stability compared to other surface coatings. Moreover, LSO anode exhibits outstanding electrolyte wettability and corrosion-resistance, with strong adhesion properties. In-situ optical microscopy observation demonstrates its stability during charge/discharge process. Symmetrical cell using the Zn-LSO anode exhibited long cycling life of 833, 455, 344, and 260 h with low overpotentials of 66, 80, 118, and 141 mV at current densities of 0.5, 1, 3 and 5 mA cm^-2, respectively. Full cells coupled with a MnO₂ cathode showed a high-capacity reversibility up to 234 mAh g^-1 and outstanding rate performance at different current densities. This study demonstrates LSO coating is a promising method for enhancing the electrochemical performance of zinc ion batteries.