Hollow spherical organic polymer artificial layer enabled stable Li metal anode

Abstract

Li metal is regarded as one of the most promising anodes in rechargeable battery systems for its high theoretical specific capacity, low redox potential and light weight. However, Li dendritic formation and low Coulombic efficiency (CE) triggered by the nonuniform Li+ deposition restrict the further step to the commercialization of lithium metal batteries. Herein, a fantastic hollow spherical porous organic polymer (HS-POP) with concentrated lithiophilic functional groups of –C=N, –OH has been synthesized and utilized as an artificial solid electrolyte interphase (SEI) to regulate the interfacial stability of Li metal anode. The compelling evidences of density functional theory (DFT) calculations and Fourier-transform infrared spectra verified the energetical lithiophilic property, which facilitates Li+ uniform transfer and nucleation with decreased energy barriers. The large cavities and well-flexible shell structure not only provide enlarged lithium storage capacity, but also act as a buffer layer during repeated Li deposition and dissolution protocols. The HS-POP modified Li anode delivered a higher CE at high current density of 2 mA cm−2, and the HS-POS@Li|S full cell demonstrates excellent performance with high reversible capacity for 400 cycles at 0.5 C.