Sulfur-doped hard carbon hybrid anodes with dual lithium-ion/metal storage bifunctionality for high-energy-density lithium-ion batteries

Bifunctional hybrid anodes (BHAs), which are both a high-performance active host material for lithium-ion storage as well as a guiding agent for homogeneous lithium metal nucleation and growth, exhibit significant potential as anodes for next-generation high-energy-density lithium-ion batteries (LIBs). In this study, sulfur-doped hard carbon nanosphere assemblies (S-HCNAs) were prepared through a hydrothermal treatment of a liquid organic precursor, followed by high-temperature thermal annealing with elemental sulfur for application as BHAs for LIBs. In a carbonate-based electrolyte containing fluoroethylene carbonate additive, the S-HCNAs showed high lithium-ion storage capacities in sloping as well as plateau voltage sections, good rate capabilities, and stable cyclabilities. In addition, high average Coulombic efficiencies (CEs) of similar to 96.9% were achieved for dual lithium-ion and lithium metal storage cycles. In the LIB full-cell tests with typical NCM811 cathodes, the S-HCNA-based BHAs containing similar to 400 mA h g(-1) of excess lithium led to high energy and power densities of similar to 500 W h kg(-1) and similar to 1695 W kg(-1), respectively, and a stable cycling performance with similar to 100% CEs was achieved.