Dendrite-Free Potassium-Oxygen Battery Based on a Liquid Alloy Anode

Wei Yu, Kah Chun Lau, Yu Lei, Ruliang Liu, Lei Qin, Wei Yang, Baohua Li, Larry A. Curtiss, Dengyun Zhai, Feiyu Kang

Research output: Contribution to journalArticlepeer-review

Abstract

The safety issue caused by the dendrite growth is not only a key research problem in lithium-ion batteries but also a critical concern in alkali metal (i.e., Li, Na, and K)-oxygen batteries where a solid metal is usually used as the anode. Herein, we demonstrate the first dendrite-free K-O2 battery at ambient temperature based on a liquid Na-K alloy anode. The unique liquid-liquid connection between the liquid alloy and the electrolyte in our alloy anode-based battery provides a homogeneous and robust anode-electrolyte interface. Meanwhile, we manage to show that the Na-K alloy is only compatible in K-O2 batteries but not in Na-O2 batteries, which is mainly attributed to the stronger reducibility of potassium and relatively more favorable thermodynamic formation of KO2 over NaO2 during the discharge process. It is observed that our K-O2 battery based on a liquid alloy anode shows a long cycle life (over 620 h) and a low discharge-charge overpotential (about 0.05 V at initial cycles). Moreover, the mechanism investigation into the K-O2 cell degradation shows that the O2 crossover effect and the ether-electrolyte instability are the critical problems for K-O2 batteries. In a word, this study provides a new route to solve the problems caused by the dendrite growth in alkali metal-oxygen batteries.

Original languageEnglish
Pages (from-to)31871-31878
Number of pages8
JournalACS Applied Materials and Interfaces
Volume9
Issue number37
DOIs
Publication statusPublished - 2017 Sep 20
Externally publishedYes

Keywords

  • K-O battery
  • Na-K alloy
  • dendrite growth
  • liquid-liquid interface
  • superoxide

ASJC Scopus subject areas

  • Materials Science(all)

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