Lithium‐Metal Batteries via Suppressing Li Dendrite Growth and Improving Coulombic Efficiency

Abstract

Lithium‐metal batteries (LMB) are recognized as one of the most promising candidates for the next generation of batteries due to their high energy density. Extensive studies have been refocused on the field in the past decade to make the technology commercially viable. Despite exciting progress that has been made, the practical application of LMBs is still hampered by the uncontrollable Li plating morphology and inferior Coulombic efficiency (CE) during cycling. Herein, first, the relevant research that has been carried out in the past decade (2010–2021) is briefly summarized and then the Li plating behaviors, mechanistic understanding of these behaviors, and strategies to suppress Li dendrite growth are discussed. Finally, the methods and techniques to improve Coulombic efficiency (CE) is discussed, especially the design of liquid electrolytes, and possible research directions for the future development of LMBs.

Size Effect of a Piezoelectric Material as a Separator Coating Layer for Suppressing Dendritic Li Growth in Li Metal Batteries

“…Figure 4 a shows the cycle performance of the Li-Cu cells at 1.0 mA cm −2 . The Coulombic efficiencies (CEs) of the cells with the pristine PP separator and LPM-coated separator dropped below 80% after 80 cycles, due to severe dendritic growth which causes dead Li and induces high internal resistance [ 47 ]. Furthermore, the cell with the SPM-coated separator maintained a high CE (90%) even at 150 cycles.…”

A self-healing polymerized-ionic-liquid-based polymer electrolyte enables a long lifespan and dendrite-free solid-state Li metal batteries at room temperature

“…Likewise, the uncontrolled Li dendritic generation throughout the cycling process may pierce the brittle separator, inducing internal short circuits and battery failure. 2–9…”

“…Likewise, the uncontrolled Li dendritic generation throughout the cycling process may pierce the brittle separator, inducing internal short circuits and battery failure. [2][3][4][5][6][7][8][9] To address such challenges, a variety of strategies, including flame-retardant additives, artificial in/ex situ solid electrolyte interphase (SEI), and the design of structured solid-state electrolytes (SSEs), have been utilized. 10,11 As an alternative to the organic liquid electrolyte, the SSE is considered more promising for safe energy storage owing to its inherent nonflammability and robust mechanical properties, which plays a pivotal role in restraining Li dendrites.…”

An Ultrafast and Stable Li‐Metal Battery Cycled at −40 °C

“…Li metal battery (LMB) is considered as a prominent candidate for the next‐generation rechargeable battery, [ 1–4 ] whereas it suffers from unstable solid‐electrolyte interphase (SEI) formation and severe Li dendrite growth on Li anode. [ 5–9 ] As the temperature drops below 0 °C, the formation of stable SEI ingredients is largely restrained due to an insufficient dynamics, leading to inhomogeneous SEIs and persistent side reactions. [ 10–13 ] Moreover, the reduced sizes of Li nuclei at low temperatures (LT) will make the exposure Li anode to the electrolyte more possible, inducing parasitic reactions, which is also unfavorable for stable operation of LMBs at LT. [ 2,11,14–17 ] Many efforts have been devoted to stabilize Li metal anode at LT, including constructing artificial SEI film, [ 18 ] engineering current collectors, [ 19 ] modifying separator, [ 20 ] optimizing solvent component, [ 21–23 ] and introducing additives.…”

“…Li metal battery (LMB) is considered as a prominent candidate for the next-generation rechargeable battery, [1][2][3][4] whereas it suffers from unstable solid-electrolyte interphase (SEI) formation and severe Li dendrite growth on Li anode. [5][6][7][8][9] As the temperature drops below 0 °C, the formation of stable SEI ingredients is largely restrained due to an insufficient dynamics, leading and cumulative cycling capacity are achieved in LT alkali metal symmetric batteries. Our study presents a great superiority of electrolyte chemistry for synergistic regulation of both ion transfer kinetics and SEI toward ultrafast and stable LT LMBs.…”