Low-temperature anode-free potassium metal batteries

• Published in: Nature communications Vol. 14; no. 1; pp. 6006 - 11
• Main Authors: Tang, Mengyao, Dong, Shuai, Wang, Jiawei, Cheng, Liwei, Zhu, Qiaonan, Li, Yanmei, Yang, Xiuyi, Guo, Lin, Wang, Hua
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 26.09.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 140/133; 140/146; 140/58; 147/135; 147/3; 639/4077/4079; 639/638/161/891; 639/638/675; Additives; Alkali metals; Copper; Electrolytes; Electrolytic cells; Humanities and Social Sciences; Low temperature; multidisciplinary; Plating; Polydimethylsiloxane; Polymers; Potassium; Science; Science (multidisciplinary); Silicon; Silicones; Solvation; Specific energy
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-41778-6

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 −1 based on the total mass of the negative and positive electrodes at 0.2 C (26 mA g −1 ) charge/discharge and −40 °C. Low temperature operation of anode-free batteries is limited by poor reversibility of metal plating/stripping. Here, via electrolyte engineering, authors enable −40 °C operation of an anode-free K metal battery by tailoring a weakly solvating electrolyte with a silicone polymer additive.