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Tremendous efforts have been made to improve the electrochemical performance of the lithium-sulfur batteries. However, challenges remain in achieving fast electronic and ionic transport while accommodate the significant cathode volumetric change. On the other hand, the severe capacity decay mainly attributed to polysulfide shuttle also hampers the practical applications. Here, we report a simple, low-cost, and eco-friendly method for the one-step preparation of a binder-free S-C composite cathode by plasma dissociation of CS2 containing gases at room-temperature. The key issue of polysulfide shuttle effect in Li-S batteries is also effectively resolved just by the introduction of N2 into the precursor gases. The electrode exhibits a high reversible capacity of ~600 mAh/g of the total hybrid of S + C at 100 mA/g after 100 cycles with an excellent initial coulombic efficiency of nearly 100%. The cells also demonstrate along cycle life and an extremely high capacity of ~306 mAh/g even after 300 cycles at 1 A/g with a high coulombic efficiency of about 100%. The proposed method will open the way for the plasma applications in facile preparation of Li-S batteries and the improvement of its electrochemical performance.

The effect of the chemical component and microstructure, not to mention their facile modification, of the coating/wrapping carbon layer on the electrochemical performance of the Si/C composite anode in lithium ion batteries (LIBs) hasn’t been actively explored although Si/C has been recognized as one of the most promising route for the high energy density LIBs. Herein we propose a novel nitrogen-plasma doping route to modify the top carbon film in an elaborately constructed layered Si/C composite anode. The electrochemical performance, e.g., the initial coulombic efficiency (CE), cycle stability and specific capacity of the composite anode is drastically improved by this plasma processing due to the increased kinetics of lithium ions. By means of the appropriate adjustment of the N doping ratio and N chemical configuration in the carbon layer through a N2/H2 plasma processing, the lithium diffusion rate in the composite anode was memorably increased as the pseudocapacitance effects promoted. The optimized Si/C composite exhibits a high capacity of 1120.7 mA h g−1 and an initial CE of 80.8% at the current of 2 A g−1 after a long cycle of 1500, increasing by ~40% of specific capacity and ~29% of the initial CE.