Jia Hao, Xu Yaobin, Burton Sarah D, Gao Peiyuan, Zhang Xianhui, Matthews Bethany E, Engelhard Mark H, Zhong Lirong, Bowden Mark E, Xiao Biwei, Han Kee Sung, Wang Chongmin, Xu Wu
Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States.
Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, United States.
ACS Appl Mater Interfaces. 2020 Dec 9;12(49):54893-54903. doi: 10.1021/acsami.0c18177. Epub 2020 Nov 23.
Lithium-ion batteries (LIBs) with high-nickel (Ni) content LiNiMnCoO ( + + = 1) (NMC with Ni ≥ 0.6) cathodes operated at high charge voltages have been considered as one of the most promising candidates for addressing the challenge of increasing energy density demand. Conventional LiPF-organocarbonate electrolytes exhibit incompatibility with such cell chemistries under certain testing conditions because of the instability of electrode/electrolyte interphases. In response to this challenge, ether-based electrolytes with finely tuned structure and composition of solvation sheaths were developed and evaluated in graphite (Gr)∥NMC811 cell chemistry in 2.5-4.4 V, despite ethers being conventionally considered to be unfavorable electrolyte solvents for LIBs because of their anodic instability above 4.0 V and cointercalation into Gr electrodes. The functional ether-based electrolytes in this work enable both excellent cycle life and high rate capability of Gr∥NMC811 cells. Mechanistic studies reveal that the unique structure and composition of the solvation sheath of the functional ether electrolytes are the main reasons behind their excellent anodic stability and effective protection of the Gr electrode and, consequently, the extraordinary cell performances when operated at high charge cutoff voltages. This work also provides a feasible approach in developing highly stable functional electrolytes for high-energy density LIBs.
具有高镍（Ni）含量LiNiMnCoO（+ + = 1）（Ni≥0.6的NMC）阴极且在高充电电压下运行的锂离子电池（LIB），被认为是应对能量密度需求不断增加这一挑战的最有前景的候选者之一。传统的LiPF-有机碳酸盐电解质在某些测试条件下与这种电池化学体系不相容，因为电极/电解质界面不稳定。为应对这一挑战，开发了具有精细调整的溶剂化鞘结构和组成的醚基电解质，并在2.5 - 4.4 V的石墨（Gr）∥NMC811电池化学体系中进行了评估，尽管醚类由于其在4.0 V以上的阳极不稳定性以及共嵌入Gr电极中，传统上被认为是不利于LIB的电解质溶剂。这项工作中的功能性醚基电解质使Gr∥NMC811电池具有出色的循环寿命和高倍率性能。机理研究表明，功能性醚电解质溶剂化鞘的独特结构和组成是其出色的阳极稳定性以及对Gr电极有效保护的主要原因，因此在高充电截止电压下运行时具有非凡的电池性能。这项工作还为开发用于高能量密度LIB的高度稳定的功能性电解质提供了一种可行的方法。
