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DOE OSTI · 1673773

A redox-active organic cation for safer metallic lithium-based batteries

Ji, Weixiao·Huang, He·Zheng, Dong·Zhang, Xiaoxiao·Ding, Tianyao·Lambert, Tristan H.·Qu, Deyang
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Abstract

Safety concerns have severely impeded the practical application of high-energy-density lithium-based batteries. Dendrite growth and overcharging can lead to particularly catastrophic thermal failure. Here we report an organic cation, trisaminocyclopropenium (TAC), as a bi-functional electrolyte additive to suppress dendrite growth and offer reversible overcharge protection for metallic lithium-based batteries. During the Li plating process, TAC cations with aliphatic chains can form a positively charged electrostatic shield around Li protrusions, repelling the approaching Li + and thereby attaining a more uniform plating. A two times longer cycle life of 300 h at 1 mA cm -2 is achieved in a Li|Li symmetric cell in comparison with the control. During the overcharging process, the redox-active TAC can repeatedly shuttle between two electrodes, maintaining the cell voltage within a safe value. A solid protection of 117 cycles (~1640 h) at 0.2 C with a 100% overcharge is achieved in a LiFePO 4 /Li 4 Ti 5 O 12 cell. This study sheds fresh light on the ability of organic cations to build safer batteries.

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Ji, Weixiao, Huang, He, Zheng, Dong, Zhang, Xiaoxiao, Ding, Tianyao, Lambert, Tristan H., Qu, Deyang. 2020-07-28. A redox-active organic cation for safer metallic lithium-based batteries. https://doi.org/10.1016/j.ensm.2020.07.038

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