“…The full cell flow mode test of PS-PI achieves >300 hours stable cycling by using the self-made flow cell (Figure S9), which indicates the promising application of this system for large-scale energy storage. We also noticed that the capacity decay occurred in the cycling process, which can be ascribed to the formation of irreversible solid by-products (Li 2 S and I 2 ), volatilization of nonaqueous solvents and temperature fluctuation after longterm operation 59,60 Experimental Materials Lithium metal was received from China Energy Lithium Co., Ltd. Sulfur (S), lithium iodide (LiI) and lithium bis(trifluoromethane) -sulfonimide (LiTFSI) were received from Shanghai Aladdin Biochemical Technology Co., Ltd. Lithium sulfide (Li 2 S) was received from Shanghai Macklin Biochemical Co., Ltd. 1,3dioxolane (DOL) and 1,2-dimethoxyethane(DME)were received from Sigma-Aldrich. Carbon paper (HCP010N) was received from Shanghai Hesen Electric Co., Ltd. Celgard 2500 was received from Suzhou Sinerno Technology Co., Ltd.…”