Meng Xiangyu, Liu Yuzhao, Guan Mengtian, Qiu Jieshan, Wang Zhiyu
State Key Lab of Fine Chemicals, Liaoning Key Lab for Energy Materials and Chemical Engineering, Dalian University of Technology, Dalian, 116024, China.
College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
Adv Mater. 2022 Jul;34(28):e2201981. doi: 10.1002/adma.202201981. Epub 2022 Jun 7.
Recent years have witnessed thriving efforts in pursuing high-energy batteries at an unaffordable cost of safety. Herein, a high-energy and safe quasi-solid-state lithium battery is proposed by solid-state redox chemistry of polymer-based molecular Li S cathode in a fireproof gel electrolyte. This chemistry fully eliminates not only the negative effect of extremely reactive Li metal and oxygen species on cell safety but also the damage of electrode reversibility by soluble redox intermediates. The molecular Li S cathode exhibits an exceptional lifetime of 2000 cycles, 100% Coulombic efficiency, high capacity of 830 mA h g with ultralow capacity loss of 0.005-0.01% per cycle and superior rate capability up to 10 C. Meanwhile, it shows high stability in the carbonate-involving electrolyte for maximizing the compatibility with carbonate-efficient Si anode. The optimized cell chemistry exerts high energy over 750 W h kg for 500 cycles with fast rate response, high-temperature adaptability, and no self-discharge. A fire-retardant composite gel electrolyte is developed to further strengthen the intrinsic safe redox between the Li S cathode and the Si anode, which secures remarkable safety against extreme abuse of overheating, short circuits, and mechanical damage in air/water or even when on fire.
近年来，人们一直在以难以承受的安全成本努力研发高能量电池。在此，通过基于聚合物的分子锂硫阴极在防火凝胶电解质中的固态氧化还原化学，提出了一种高能量且安全的准固态锂电池。这种化学方法不仅完全消除了极具反应性的锂金属和氧物种对电池安全的负面影响，还消除了可溶性氧化还原中间体对电极可逆性的损害。分子锂硫阴极表现出2000次循环的超长寿命、100%的库仑效率、830 mA h g的高容量、每循环超低的0.005 - 0.01%的容量损失以及高达10 C的优异倍率性能。同时，它在含碳酸盐的电解质中表现出高稳定性，以最大限度地提高与高效碳酸盐硅阳极的兼容性。优化后的电池化学体系在500次循环中具有超过750 W h kg的高能量，具有快速的速率响应、高温适应性且无自放电现象。开发了一种阻燃复合凝胶电解质，以进一步加强锂硫阴极与硅阳极之间的固有安全氧化还原反应，确保在空气/水中甚至着火时，能有效抵御过热、短路和机械损伤等极端滥用情况，具有卓越的安全性。
