Carbonized polymer dots functionalized graphene to regulate lithium homogenous deposition and SEI formation dynamics

Abstract

Flexible lithium metal anode with ultrahigh theoretical specific capacity suffers from uncontrollable growth of lithium dendrite and severe volume changes during Li plating/stripping process. To address these issues, a novel kind of flexible graphene oxide (GO) film anchored with carbonized polymer dots (CPDs) (CPD@GO) composite substrate was fabricated via a one-step microwave approach in which CPDs successfully regulate the dispersion and interlayer spacing of GO. Nanoscale CPDs act as lithiophilic nucleation sites to promote Li uniform deposition between the interlayers rather than on the surface of GO. The abundant surface functional groups of CPDs result in the generation of more stable components for solid electrolyte interphase (SEI) with high ionic conductivity of LiF and Li3N through accelerating the degradation dynamics of lithium salt. As a result, the obtained lithium anode presents small fluctuant profiles with lower voltage hysteresis (10.5 mV after 2600 h of operation at 1.0 mA cm−2). The coin and pouch full cells constructed with LiFePO4 remain decent cycling performance. This work paves a new sight for the application of carbon materials in energy storage devices.