In Situ Synthesis of Li2S-Loaded amphiphilic Porous Carbon and Modification of the Li2S Electrode for Long-Life Li2S Batteries

A strategy to construct amphiphilic inner surfaces with hydrophilic N, S O and C S C sites in porous carbon is presented for applications in Li2S batteries. The amphiphilic porous carbon (APC) with high wettability, specific surface area, and polysulfide (PS) absorption ability is obtained through the pyrolysis of a glucose-thiourea resin with a nano-CaCO3 template. Furthermore, a Li2S-loaded APC is developed in which Li2SO4 is employed instead of CaCO3. Li2SO4 is not only a reactant for Li2S production, but also functions as a template to form mesopores. Sulfur blending in the Li2S electrode successfully improves the electrode activation. The initial capacity decay is suppressed significantly after the Li2S electrode is modified with a protective layer composed of polyethylene oxide and polybenzimidazole. The first discharge capacity reaches 1082 mAhg(-1) Li2S (equivalent to 1554 mAhg(-1)S). The resultant Li2S battery exhibits excellent cyclability. A discharge capacity as high as 565 mAhg(-1) is retained after 300 cycles at a discharge rate of 0.5 C.A rate capacity of 376 mAhg(-1) is achieved at 5 C.