Liu Sufu, Xia Jiale, Zhang Weiran, Wan Hongli, Zhang Jiaxun, Xu Jijian, Rao Jiancun, Deng Tao, Hou Singyuk, Nan Bo, Wang Chunsheng
Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20740, USA.
Department of Materials Science and Engineering, University of Maryland, College Park, MD 20740, USA.
Angew Chem Int Ed Engl. 2022 Oct 24;61(43):e202210522. doi: 10.1002/anie.202210522. Epub 2022 Sep 21.
The instability of carbonate electrolyte with metallic Li greatly limits its application in high-voltage Li metal batteries. Here, a "salt-in-salt" strategy is applied to boost the LiNO solubility in the carbonate electrolyte with Mg(TFSI) carrier, which enables the inorganic-rich solid electrolyte interphase (SEI) for excellent Li metal anode performance and also maintains the cathode stability. In the designed electrolyte, both NO and PF anions participate in the Li -solvent complexes, thus promoting the formation of inorganic-rich SEI. Our designed electrolyte has achieved a superior Li CE of 99.7 %, enabling the high-loading NCM811||Li (4.5 mAh cm ) full cell with N/P ratio of 1.92 to achieve 84.6 % capacity retention after 200 cycles. The enhancement of LiNO solubility by divalent salts is universal, which will also inspire the electrolyte design for other metal batteries.
碳酸盐电解质与金属锂之间的不稳定性极大地限制了其在高压锂金属电池中的应用。在此，采用了一种“盐包盐”策略来提高LiNO在含有Mg(TFSI)载体的碳酸盐电解质中的溶解度，这使得富含无机成分的固体电解质界面（SEI）具备优异的锂金属阳极性能，同时还能维持阴极稳定性。在设计的电解质中，NO 和PF 阴离子均参与锂-溶剂络合物的形成，从而促进富含无机成分的SEI的形成。我们设计的电解质实现了99.7%的优异锂库仑效率，使N/P比为1.92的高负载NCM811||Li（4.5 mAh cm ）全电池在200次循环后容量保持率达到84.6%。二价盐对LiNO溶解度的增强作用具有普遍性，这也将为其他金属电池的电解质设计提供启发。
