Lithium sulfide nanocrystals as cathode materials for advanced batteries

The ever-increasing need for sustainable development requires advanced battery techniques beyond the current generation of lithium ion batteries. Among all candidates being explored, lithium-sulfur batteries are a very promising system to be commercialized in the near future. Towards this end, the development of lithium sulfide (Li2S) nanocrystal-based cathodes has received tremendous effort and witnessed multiple reviews. Differentiated from the focus on performance improvement in previous reviews, this review summarizes the research progress in line with the approaches of materials synthesis and electrode fabrication. The key chemistry, operation procedure, materials characterizations and performance assessments are all given a balanced description. Moreover, all approaches are collectively analyzed along the lines of six criteria towards practical applications, i.e., electrode performance, materials quality, resources sustainability, production cost, operation procedure, and consumed energy. Finally, some perspective viewpoints on the future research directions are offered.