Advanced Lithium Ion Sulfur Battery Based on Spontaneous Electrochemical Exfoliation/Lithiation of Graphite in Nonaqueous Electrolytes

An advanced lithium ion sulfur battery is constructed on the foundation of spontaneous electrochemical exfoliation and lithiation of graphite in nonaqueous electrolytes, in which to produce a high-quality graphene matrix for the sulfur cathode and lithiated graphite for the anode, respectively. On one hand, the high-quality graphene, obtained via spontaneous electrochemical exfoliation of graphite in propylene-carbonate-based electrolyte, works as a matrix to improve the conductivity of sulfur and trap the polysulfides. On the other hand, the lithiated graphite anode, obtained by spontaneous electrochemical lithiation of graphite in ethylene-carbonate-based electrolyte with 5 wt % fluoroethylene-carbonate additive, provides ample lithium ion sources and increases the safety coefficient of the lithium ion sulfur battery. Meanwhile, the fluoroethylene-carbonate additive can derive a LiF-rich solid electrolyte interphase on a lithiated graphite anode, which can in turn mitigate the notorious shuttle effect. More attractively, the spontaneous electrochemical exfoliation and lithiation method can produce high-quality graphene and lithiated graphite in large scale and without electric energy consumption. Therefore, this approach shows great potential for the configuration of an advanced lithium ion sulfur battery with enhanced safety and high energy density.