Anion-Polarity-Induced Interfacial Reconstruction Directs Crystallographic Texture for Highly Reversible Sn Anodes.

Abstract

Controllable Sn electrodeposition is crucial for achieving highly reversible Sn metal batteries, but remains a significant challenge. Here, preferential exposure of Sn(211) planes with a uniform and compact morphology is achieved via an anion-polarity-driven interfacial regulation strategy during plating and stripping. Strong and crystallographically selective adsorption of CF₃SO₃ ^- on Sn effectively modulates deposition behavior. Owing to its large intrinsic dipole, CF₃SO₃ ^- establishes a pronounced surface-normal interfacial dipole field on Sn(211), which suppresses growth along this plane while accelerating deposition on competing orientations, thereby driving the gradual evolution toward dominant Sn(211) exposure. Consequently, the reconstructed Sn anode delivers outstanding performance, including 99.88% Coulombic efficiency over 10,200 cycles at 10 mA cm^-2 in Sn//Cu cells, ultralong cycling stability of 3456 h (∼4.8 months) in Sn//Sn symmetric cells, and 71% capacity retention after 20,000 cycles in full cells. The dipole-based interfacial descriptor proposed in this work correlates anion polarity with crystallographic texture evolution in metal electrodeposition, providing a rational route toward controllable electrochemical reconstruction for high-performance metal batteries.