Dendrite‐accelerated thermal runaway mechanisms of lithium metal pouch batteries

Abstract

High‐energy‐density lithium metal batteries (LMBs) are widely accepted as promising next‐generation energy storage systems. However, the safety features of practical LMBs are rarely explored quantitatively. Herein, the thermal runaway behaviors of a 3.26 Ah (343 Wh kg−1) Li | LiNi0.5Co0.2Mn0.3O2 pouch cell in the whole life cycle are quantitatively investigated by extended volume‐accelerating rate calorimetry and differential scanning calorimetry. By thermal failure analyses on pristine cell with fresh Li metal, activated cell with once plated dendrites, and 20‐cycled cell with large quantities of dendrites and dead Li, dendrite‐accelerated thermal runaway mechanisms including reaction sequence and heat release contribution are reached. Suppressing dendrite growth and reducing the reactivity between Li metal anode and electrolyte at high temperature are effective strategies to enhance the safety performance of LMBs. These findings can largely enhance the understanding on the thermal runaway behaviors of Li metal pouch cells in practical working conditions.

Thermally Stable Polymer‐Rich Solid Electrolyte Interphase for Safe Lithium Metal Pouch Cells

“…The corresponding heat production rate of 4.3 mW À 1 is sufficient to cause the cell to self-heat. [8,9] As the temperature rises toward the melting point of Li metal, this reaction is intensified and a peak rises at 261.3 °C (20.7 mW mg À 1 ) is observed, which is strong enough to trigger thermal runaway. The polymer SEI layer with high thermal stability introduced by MFA can greatly suppress this hazard and the reaction temperature of Li and MFA electrolyte can be raised to 390.3 °C.…”

Synergy of an In Situ-Polymerized Electrolyte and a Li3N–LiF-Reinforced Interface Enables Long-Term Operation of Li-Metal Batteries

“…The recent quantitative investigations verify that the exothermic reaction between Li metal and electrolytes triggers the thermal runaway of cycled cells. − The proper regulation of the electrolyte is an effective strategy to stabilize the Li-anode surface. − The electrolytes can be categorized as liquid, quasi-solid-state, and all-solid-state according to phase difference at room temperature. In spite of the severe dendrite growth, the liquid electrolytes offer the benefits of high conductivity and wettability. , All-solid electrolytes with high mechanical strength have shown superiority in suppressing Li dendrites.…”

Coordinating ionic and electronic conductivity on 3D porous host enabling deep dense lithium deposition toward high-capacity lithium metal anodes

“…4,5 However, uncontrollable dendrite growth and enormous volume change remain the major defects of Li metal anodes, which would cause battery safety problems such as internal short circuits, swelling, and thermal runaway. [6][7][8][9] Various strategies have been proposed to overcome the troubles, such as electrolyte additives, artificial solid electrolyte interface (SEI), and structural Li anodes. [10][11][12][13][14][15][16][17][18][19][20] Compositing metallic Li within a three-dimensional (3D) porous host is considered effective for resolving problems of both dendritic Li and volume change.…”