首页|Unraveling the incompatibility mechanism of ethylene carbonate-based electrolytes in sodium metal anodes

Unraveling the incompatibility mechanism of ethylene carbonate-based electrolytes in sodium metal anodes

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Ethylene carbonate(EC)is widely used in lithium-ion batteries due to its optimal overall performance with satisfactory conductivity,relatively stable solid electrolyte interphase(SEI),and wide electrochem-ical window.EC is also the most widely used electrolyte solvent in sodium ion batteries.However,com-pared to lithium metal,sodium metal(Na)shows higher activity and reacts violently with EC-based electrolyte(NaPF6 as solute),which leads to the failure of sodium metal batteries(SMBs).Herein,we reveal the electrochemical instability mechanism of EC on sodium metal battery,and find that the com-bination of EC and NaPF6 is electrically reduced in sodium metal anode during charging,resulting in the reduction of the first coulombic efficiency,and the continuous consumption of electrolyte leads to the cell failure.To address the above issues,an additive modified linear carbonate-based electrolyte is provided as a substitute for EC based electrolytes.Specifically,ethyl methyl carbonate(EMC)and dimethyl carbon-ate(DMC)as solvents and fluoroethylene carbonate(FEC)as SEI-forming additive have been identified as the optimal solvent for NaFP6 based electrolyte and used in Na4Fe3(PO4)2(P2O7)||Na batteries.The batter-ies exhibit excellent capacity retention rate of about 80％over 1000 cycles at a cut-off voltage of 4.3 V.

Na metal batteriesEthylene carbonate decompositionNa4Fe3(PO4)2(P2O7)cathodeInterface engineeringEthylene carbonate-free electrolyte

Daomin Qin、Fangyuan Cheng、Meilian Cao、Feiyang Yan、Qian Wang、Chun Fang、Jiantao Han

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State Key Laboratory of Material Processing and Die & Mould Technology,School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,Hubei,China

National Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaChina Postdoctoral Science FoundationChina Postdoctoral Science Foundation

521722015173200551902118521022492019M6626092020T130217

2024

10.1016/j.jechem.2024.02.012

能源化学
中国科学院大连化学物理研究所 中国科学院成都有机化学研究所

能源化学

CSTPCDEI
影响因子：0.654
ISSN：2095-4956
年,卷(期)：2024.94(7)