Novel S-doped ordered mesoporous carbon nanospheres toward advanced lithium metal anodes

Abstract

Lithium metal anode has been considered as an ideal anode for the next generation lithium batteries owing to its high energy density. However, its practical application is still limited by the low Coulombic efficiency and poor safety performance due to the lithium dendrites caused by uncontrollable lithium deposition and unstable solid electrolyte interphase. In this work, we report for the first time the in-situ synthesis of S-doped carbon nanospheres with ordered mesoporous channels used as the functional scaffold for safe and stable lithium metal anode. S-doping, large surface area and ordered mesoporous structure of the carbon spheres provide homogenous nucleation sites, regulated local current density and facilitated mass transport, which induce uniform lithium nucleation and the subsequent dendrite-free growth. As a result, the fabricated anode exhibits high Coulombic efficiency up to ~97.5% within 220 cycles. The symmetric cell also presents stable potential hysteresis below 15 mV with ultralong cycling life up to 1600 h at a current density of 0.5 mA cm-2. Full cell coupled with commercial LiFePO4 as cathode delivers a high reversible capacity of ~135.0 mAh g-1 after 300 cycles at 1 C, showing high potential in practical application as stable lithium metal anodes.