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Effectively Regulating More Robust Amorphous Li Clusters for Ultrastable Dendrite-Free Cycling.

Shizhi HuangJunfeng YangLuxiang MaJingyi DingXusheng WangChengyuan PengBinglu ZhaoMengxiong CaoJunrong ZhengXin-Xiang ZhangJitao Chen
Published in: Advanced science (Weinheim, Baden-Wurttemberg, Germany) (2021)
A disordered phase in Li-deposit nanostructure is greatly attractive, but plagued by the uncontrollable and unstable growth, and the nanoscale characterization in the structure. Here, fully characterized in cryogenic transmission electron microscopy (cryo-TEM), more robust amorphous-Li (ALi) clusters are revealed and effectively regulated on heteroatom-activating electronegative sites and an advanced solid electrolyte interphase (SEI) layer. Heteroatom-activating electronegative sites capably enhance the electrostatic interaction of Li+ and heteroatom-doping graphene-like film (HDGs), meaning lower Li diffusion barrier and larger binding energy that is confirmed by small nucleation overpotentials of 13.9 and 10 mV at 0.1 mA cm-2 in the fluoroethylene carbonate-adding ester-based (FEC-ester) and LiNO3 -adding ether-based (LiNO3 -ether) electrolytes. Orderly multilayer SEI structure comprised of inorganic-rich components enables fast ion transports and durable capabilities to construct highly reversible and long-term plating/stripping cycling. ALi cluster anodes exhibit non-crystalline morphologies and perform ultrastable dendrite-free cycling over 2800 times. Stable ALi clusters are also grown in LiFePO4 (LFP) (LFP-ALi-HDGs-N||LiFePO4 [LFP]) full cells with advantageous capacities up to 165.5 and 164.3 mAh g-1 in these optimized electrolytes at 0.1 C; the remarkable capacity retentions maintain to 93% and 91% after 150 cycles at 0.2 C. Structure viability, electrochemical reversibility, and excellent performance in ALi clusters are effectively regulated.
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