Polymer-free electrospun separator film comprising silica nanofibers and alumina nanoparticles for Li-ion full cell

A separator film for high-performance Li-ion batteries was prepared by electrospinning. The film had a hybrid morphology of silica nanofibers(SNFs) and alumina nanoparticles(ANPs), with a smooth surface, polymer-free composition, high porosity(79%), high electrolyte uptake(876%), and excellent thermal stability. Contact angle measurements demonstrated the better immersion capability of the SNF-ANP separator film for commercial liquid electrolytes than a commercial CELGARD 2500 separator film. Moreover,compared to the commercial CELGARD 2500 separator, the ionic conductivity of the SNF-ANP separator film was nearly three times higher, the bulk resistance was lower at elevated temperature(120 ℃), the interfacial resistance with lithium metal was lower, and the electrochemical window was wider. Full cells were fabricated to determine the cell performance at room temperature. The specific capacity of the full cell with the SNF-ANP separator film was 165 mAh g-1;the cell was stable for 100 charge/discharge cycles and exhibited a capacity retention of 99.9%. Notably, the electrospun SNF-ANP separator film can be safely used in Li-ion or Li-S rechargeable batteries.

A review on lithium-sulfur batteries:Challenge,development,and perspective

Lithium-sulfur(Li-S)battery is recognized as one of the promising candidates to break through the specific energy limitations of commercial lithium-ion batteries given the high theoretical specific energy,environmental friendliness,and low cost.Over the past decade,tremendous progress have been achieved in improving the electrochemical performance especially the lifespan by various strategies mainly concentrated on the sulfur cathodes.In this review,the fundamental electrochemistry of sulfur cathode and lithium anode is revealed to understand the current dilemmas.And the advances achieved through diverse strategies are comprehensively summarized,which involves lithium polysulfides(LiPSs)limitation,sulfur redox reaction regulation and electrocatalysis in sulfur cathode and artificial solid electrolyte interface(SEI),electrolyte design,and structured anode in lithium anode.Additionally,the differences between laboratory level coin cells and actual pouch cells need to be addressed that only few reports on practical Li-S pouch cell are available due to the unexpected problems on both sulfur cathode and lithium anode which are masked at lithium and electrolyte excess.Lastly,the challenges and perspective toward the practical Li-S batteries are also offered.