Cationic Surfactant-Based Electrolyte Additives for Uniform Lithium Deposition via Lithiophobic Repulsion Mechanisms

Hongliu Dai; Kai Xi; Xin Liu; Chao Lai; Shanqing Zhang

doi:10.1021/jacs.8b08963

Cationic Surfactant-Based Electrolyte Additives for Uniform Lithium Deposition via Lithiophobic Repulsion Mechanisms

J Am Chem Soc. 2018 Dec 19;140(50):17515-17521. doi: 10.1021/jacs.8b08963. Epub 2018 Dec 11.

Authors

Hongliu Dai¹, Kai Xi², Xin Liu¹, Chao Lai¹, Shanqing Zhang³

Affiliations

¹ School of Chemistry and Materials Science , Jiangsu Normal University , Xuzhou , Jiangsu 221116 , China.
² Department of Materials Science and Metallurgy , University of Cambridge , Cambridge CB3 0FS , U.K.
³ Center for Clean Environment and Energy, School of Environment and Science , Griffith University , Brisbane , Queensland 4222 , Australia.

PMID: 30486645
DOI: 10.1021/jacs.8b08963

Abstract

Lithium metal is among the most promising anode materials for high-energy batteries due to its high theoretical capacity and lowest electrochemical potential. However, dendrite formation is a major challenge, which can result in fire and explosion of the batteries. Herein, we report on hexadecyl trimethylammonium chloride (CTAC) as an electrolyte additive that can suppress the growth of lithium dendrites by lithiophobic repulsion mechanisms. During the lithium plating process, cationic surfactant molecules can aggregate around protuberances via electrostatic attraction, forming a nonpolar lithiophobic protective outer layer, which drives the deposition of lithium ions to adjacent regions to produce dendrite-free uniform Li deposits. Thus, an excellent cycle of 300 h at 1.0 mA cm^-2 and rate performance up to 4 mA cm^-2 are available safely in symmetric Li|Li cells. In particular, significantly enhanced cycle and rate performance were achieved when the electrolyte with CTAC additives was used in lithium-sulfur and Li|LiNi_0.5Co_0.2Mn_0.3O₂ full cells. The effects of carbon chains, anions of surfactant, and electrostatic repulsion on the deposition of lithium anodes are reported. This work advances research in inhibiting Li dendrite growth with a new electrolyte additive based on cationic surfactants.