Nitrate Additives Coordinated with Crown Ether Stabilize Lithium Metal Anodes in Carbonate Electrolyte |
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Authors: | Sichen Gu Si-Wei Zhang Junwei Han Yaqian Deng Chong Luo Guangmin Zhou Yanbing He Guodan Wei Feiyu Kang Wei Lv Quan-Hong Yang |
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Affiliation: | 1. Shenzhen Key Laboratory for Graphene-based Materials, Engineering Laboratory for Functionalized Carbon Materials, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055 China;2. Shenzhen Geim Graphene Center (SGC), Tsinghua-Berkeley Shenzhen Institute (TBSI), Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055 China;3. Nanoyang Group, State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China |
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Abstract: | Lithium metal anodes (LMAs) are promising for next-generation batteries but have poor compatibility with the widely used carbonate-based electrolytes, which is a major reason for their severe dendrite growth and low Coulombic efficiency (CE). A nitrate additive to the electrolyte is an effective solution, but its low solubility in carbonates is a problem that can be solved using a crown ether, as reported. A rubidium nitrate additive coordinated with 18-crown-6 crown ether stabilizes the LMA in a carbonate electrolyte. The coordination promotes the dissolution of NO3? ions and helps form a dense solid electrolyte interface that is Li3N-rich which guides uniform Li deposition. In addition, the Rb (18-crown-6)+ complexes are adsorbed on the dendrite tips, shielding them from Li deposition on the dendrite tips. A high CE of 97.1% is achieved with a capacity of 1 mAh cm?2 in a half cell, much higher than when using the additive-free electrolyte (92.2%). Such an additive is very compatible with a nickel-rich ternary cathode at a high voltage, and the assembled full battery with a cathode material loading up to 10 mg cm?2 shows an average CE of 99.8% over 200 cycles, indicating a potential for practical use. |
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Keywords: | carbonate electrolytes crown ether high voltage cathodes lithium metal batteries nitrate additives |
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