“Mobius strip-like” FeSn alloy: A novel highly-distorted 3D hierarchical porous anode for ultrafast and stable Li storage
Huanyan Liu, Jizhou Zhang, Xiang Peng, Shichao Zhang, San‐Qiang Shi, Wenbo Liu
Abstract
Tin provides high specific capacity (994 mAh g −1 ) by forming Li 4.4 Sn in lithium-ion batteries (LIBs) yet exhibits poor electrochemical stability. Inspired by the miraculous “Mobius strip” with superior stress-relieving effect in the developable surface, herein, through a facile dealloying and sol-gel pyrolysis method, a “Mobius strip-like” highly-distorted C-wrapped 3D hierarchical porous FeSn integrated anode (HD-3D-HP FeSn@C) is initially designed and utilized to relieve the mechanical stress in Sn-based anode generated during lithiation-delithiation. The anodes are characteristic of highly-distorted bimodal pore-size distribution composed of microporous architecture and homogeneous nanopores on pore walls on the developable surface, which contribute to effective stress relief and rapid mass transfer. Moreover, the wrapped-C is of great significance for maintaining the anode structure and improving the stability of solid electrolyte interface (SEI). Therefore, the HD-3D-HP FeSn@C anodes display the ultrafast Li storage properties with high rate capability (0.23 mAh cm −2 at 10 mA cm −2 ) and good cycling stability (68.89 % of capacity retention after 1000 cycles at 1 mA cm −2 , only ∼0.03 % capacity decay per cycle). This work provides a novel and universal anode design philosophy towards high-performance LIBs, which may shed light on the evolution of other secondary batteries beyond alkali metal batteries.