Holoubek John, Liu Haodong, Wu Zhaohui, Yin Yijie, Xing Xing, Cai Guorui, Yu Sicen, Zhou Hongyao, Pascal Tod A, Chen Zheng, Liu Ping
Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA.
Program of Chemical Engineering, University of California, San Diego, La Jolla, CA 92093, USA.
Nat Energy. 2021;2021. doi: 10.1038/s41560-021-00783-z. Epub 2021 Feb 25.
Lithium metal batteries (LMBs) hold the promise to pushing cell level energy densities beyond 300 Wh kg while operating at ultra-low temperatures (< -30°C). Batteries capable of both charging and discharging at these temperature extremes are highly desirable due to their inherent reduction of external warming requirements. Here we demonstrate that the local solvation structure of the electrolyte defines the charge-transfer behavior at ultra-low temperature, which is crucial for achieving high Li metal coulombic efficiency (CE) and avoiding dendritic growth. These insights were applied to Li metal full cells, where a high-loading 3.5 mAh cm sulfurized polyacrylonitrile (SPAN) cathode was paired with a one-fold excess Li metal anode. The cell retained 84 % and 76 % of its room temperature capacity when cycled at -40 and -60 °C, respectively, which presented stable performance over 50 cycles. This work provides design criteria for ultra-low temperature LMB electrolytes, and represents a defining step for the performance of low-temperature batteries.
锂金属电池（LMBs）有望在超低温（< -30°C）下运行时将电池级能量密度提高到300 Wh/kg以上。由于其固有地减少了外部加热需求，能够在这些极端温度下进行充电和放电的电池是非常理想的。在这里，我们证明了电解质的局部溶剂化结构定义了超低温下的电荷转移行为，这对于实现高锂金属库仑效率（CE）和避免枝晶生长至关重要。这些见解被应用于锂金属全电池，其中高负载3.5 mAh/cm²的硫化聚丙烯腈（SPAN）阴极与过量一倍的锂金属阳极配对。当在-40°C和-60°C下循环时，该电池分别保留了其室温容量的84%和76%，并在50次循环中表现出稳定的性能。这项工作为超低温LMB电解质提供了设计标准，并代表了低温电池性能的一个决定性步骤。
