Grafting polyethyleneimine onelectrospun nanofiber separator to stabilize lithium metal anode for lithiumsulfur batteries
MengfeiHu, Qingyan Ma, Yuan Yuan, Yankai Pan, Mingqi Chen, Yayun Zhang*, Donghui Long*
Chemical Engineering Journal, 2020, 388, 124258.
文章链接：https://www.sciencedirect.com/science/article/pii/S1385894720302497?via%3Dihub
High-energy-density lithium sulfur (Li-S)batteries are suffering several seemingly insurmountable barriers, including lithiumdendrite formation and polysulfides shuttling. Functional separator, whichbridges anode, electrolyte and cathode together, has the potential to offer aperfect solution to these concerns. Herein, we develop a functional ammoniatedpolyacrylonitrile (PAN) nanofiber separator (APANF) which can simultaneouslyinhibit Li dendrite formation and polysulfides shuttling. Branchedpolyethyleneimine (PEI) are fixed on the electrospun PAN nanofiber mat via achemical grafting to provide amino groups. Such strongly polar separator canwell regulate the uniform Li ions distribution and induce the formation of theLi3N-rich SEI layer, resulting in an interesting 3D spherical anddendrite-free Li deposit pattern. The coulombic efficiency of resulting Lianode can be improved up to 98.8% with a low overpotential of 15 mV.Meanwhile, the separator can also serve as a block for polysulfides shuttingdue to the strong chemical adsorption capability of PEI, thus facilitating thecapacity retention of sulfur cathode. This work provides an easy and scalablealternative to conventional polyolefin separators for solving problems in bothanode and cathode of Li-S battery.
