Flexible Amalgam Film Enables Stable Lithium Metal Anodes with High Capacities

Abstract

Dendrite formation is a critical challenge for the applications of lithium (Li) metal anodes. In this work a new strategy is demonstrated to address this issue by fabricating an Li amalgam film on its surface. This protective film serves as a flexible buffer that affords repeated Li plating/stripping. In symmetric cells, the protected Li electrodes exhibit stable cycling over 750 hours at a high plating current and capacity of 8 mA cm−2 and 8 mAh cm−2, respectively. Coupled with high‐loading cathodes (ca. 12 mg cm−2) such as LiFePO4 and LiNi0.6Co0.2Mn0.2O2, the protected hybrid anodes demonstrate significantly improved cell stability, indicating its reliability for practical development of Li metal batteries. Interfacial analyses reveal a unique plating‐alloying synergistic function of the protective film, where Li beneath the film is actively involved in the electrode reactions upon cycling. Lithium amalgams enrich the alloy anode family and provide new perspectives for the rational design of dendrite‐free anodes.

In Situ Electrolyte Gelation to Prevent Chemical Crossover in Li Metal Batteries

“…However, the situation is remarkably altered when applying high loading cathode (12 mg cm -2 ) since the artificial solid-state interphase (SEI) layer cannot completely avoid the undesired reactions with the electrolyte at the surface upon Li plating/stripping. [20,21] The implementation of solid-state electrolytes (SSEs) in LMBs is an effective method to develop safe Li metal anodes toward stable CEI. [22][23][24] Considering the large volume variation of Li metal anodes, the efficient Li|electrolyte interface is a key factor for the successful operation of SSEs in LMBs.…”

“…However, the situation is remarkably altered when applying high loading cathode (12 mg cm –2 ) since the artificial solid‐state interphase (SEI) layer cannot completely avoid the undesired reactions with the electrolyte at the surface upon Li plating/stripping. [ 20,21 ]…”

A Self‐Healing Amalgam Interface in Metal Batteries

“…The growing demands for energy storage systems with high energy density has renewed researcher's interest in metal batteries, such as lithium (Li), sodium (Na), potassium (K), aluminum (Al), zinc (Zn), and magnesium (Mg), [1][2][3][4][5][6][7][8][9] because of the high theoretical capacity (Li: 3860 mAh g −1 , Na: 1166 mAh g −1 , K: 687 mAh g −1 , Al: 2978 mAh g −1 , Zn: 820 mAh g −1 , and Mg: 2206 mAh g −1 ) and moderate electrochemical potential (Li:…”

“…The growing demands for energy storage systems with high energy density has renewed researcher's interest in metal batteries, such as lithium (Li), sodium (Na), potassium (K), aluminum (Al), zinc (Zn), and magnesium (Mg), [ 1–9 ] because of the high theoretical capacity (Li: 3860 mAh g −1 , Na: 1166 mAh g −1 , K: 687 mAh g −1 , Al: 2978 mAh g −1 , Zn: 820 mAh g −1 , and Mg: 2206 mAh g −1 ) and moderate electrochemical potential (Li: −3.04 V, Na: −2.71 V, K: −2.93 V, Al: −2.069 V, Zn: −0.7618 V, and Mg: −2.372 V versus the standard hydrogen potential) of metal anodes. Despite these advantages, metal battery anodes still face significant challenges including metal dendrite growth and large volume change during cycling, which could cause severe safety issues of metal batteries and lead to their short cycling life.…”

“…[ 37 ] A latest research has also shown that fabricating a Li amalgam protection layer on the Li metal surface can realize lithium‐dendrite‐free anode. [ 4 ] Thus, amalgam film grown by a facile in situ alloying process on the corresponding metal anode surface could be a potential candidate as artificial SEI layer with self‐healing feature in the metal batteries.…”