Breaking Performance Limits of Zn Anodes in Aqueous Batteries by Tailoring Anion and Cation Additives
Zhaoxu Mai, Yuexing Lin, Jingying Sun, Chenhui Wang, Gongzheng Yang, Chengxin Wang, Chengxin Wang, Chengxin Wang
Abstract
Abstract Crystallographic engineering of Zn anodes to favor the exposure of (002) planes is an effective approach for improving stability in aqueous electrolytes. However, achieving non-epitaxial electrodeposition with a pronounced (002) texture and maintaining this orientation during extended cycling remains challenging. This study questions the prevailing notion that a single (002)-textured Zn anode inherently ensures superior stability, showing that such anodes cannot sustain their texture in ZnSO 4 electrolytes. We then introduced a novel electrolyte additive, benzyltriethylammonium chloride (TEBAC), which preserves the (002) texture over prolonged cycling. Furthermore, we successfully converted commercial Zn foils into highly crystalline (002)-textured Zn without any pretreatment. Experiments and theoretical calculations revealed that the cationic TEBA + selectively adsorbs onto the anode surface, promoting the exposure of the Zn(002) plane and suppressing dendrite formation. A critical discovery was the pitting corrosion caused by chloride ions from TEBAC, which we mitigated by anion substitution. This modification leads to a remarkable lifespan of 375 days for the Zn||Zn symmetric cells at 1 mA cm −2 and 1 mAh cm −2 . Furthermore, a TEBA + -modified Zn||VO 2 full cell demonstrates high specific capacity and robust cycle stability at 10.0 A g −1 . These results provide valuable insights and strategies for developing long-life Zn ion batteries.