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 circuits in aqueous zinc-ion batteries. Herein, a multifunctional zinc silicate polymer lithium polysilicate (LSO) was proposed to address the issues. LSO can prevent direct contact between electrolytes and zinc anodes, thereby suppressing severe dendrite growth. Its mechanically stable structure can restrain the stress release to further stabilize the electrode. In addition, LSO is chemically bonded to zinc anodes to ensure superior overall stability compared to other surface coatings. Moreover, LSO anodes exhibit outstanding electrolyte wettability and corrosion resistance, with strong adhesion properties. In-situ optical microscopy observation demonstrates its stability during charge/discharge process. Symmetrical cells 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 of up to 234 mAh g-1and outstanding rate performance at different current densities. This study demonstrates that LSO coating is a promising method for enhancing the electrochemical performance of zinc-ion batteries.