Low-temperature anode-free potassium metal batteries.

Tang, Mengyao; Dong, Shuai; Wang, Jiawei; Cheng, Liwei; Zhu, Qiaonan; Li, Yanmei; Yang, Xiuyi; Guo, Lin et al. · Nat Commun · 2023

basic_science · Level V

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Abstract

In contrast to conventional batteries, anode-free configurations can extend cell-level energy densities closer to the theoretical limit. However, realizing alkali metal plating/stripping on a bare current collector with high reversibility is challenging, especially at low temperature, as an unstable solid-electrolyte interphase and uncontrolled dendrite growth occur more easily. Here, a low-temperature anode-free potassium (K) metal non-aqueous battery is reported. By introducing Si-O-based additives, namely polydimethylsiloxane, in a weak-solvation low-concentration electrolyte of 0.4 M potassium hexafluorophosphate in 1,2-dimethoxyethane, the in situ formed potassiophilic interface enables uniform K deposition, and offers K||Cu cells with an average K plating/stripping Coulombic efficiency of 99.80% at -40 °C. Consequently, anode-free Cu||prepotassiated 3,4,9,10-perylene-tetracarboxylicacid-dianhydride full batteries achieve stable cycling with a high specific energy of 152 Wh kg<sup>-1</sup> based on the total mass of the negative and positive electrodes at 0.2 C (26 mA g<sup>-1</sup>) charge/discharge and -40 °C.