12 years roadmap of the sulfur cathode for lithium sulfur batteries (2009-2020)

Research interest in sulfur cathode employed in lithium sulfur battery (LSB) has been greatly aroused since 2009 due to its inherently high theoretical capacity and likely low manufacturing cost. In the span of 12 years, extensive efforts have been devoted to the scientific and technological solutions to its inherent drawbacks, including electrically isolated nature of S and Li2S, severe shuttle effect of lithium polysulfides and large volume change from S to Li2S upon lithiation. Moreover, the latest research realm of sulfur cathode is frequently emphasized towards its validity in practical applications. In this review, we focus exclusively on a research roadmap of 12 years in sulfur cathode development. We begin with a retrospect of the major conceptions and breakthroughs in different aspects to advance sulfur cathode. Additionally, we detail the major contributions from various countries, institutions, corresponding authors, journals and patents. Herein, we hope to give a comprehensively evolutionary story of sulfur cathode and new insight into the future direction of sulfur cathode, namely, carbon architecture design of sulfur host, advanced characterization techniques for in-depth mechanism understanding and full-cell evaluation for a truly viable LSB. We believe more researches into sulfur cathode should be warranted to understand relevant material chemistries, interfaces and engineering present in the LSBs, consequently bringing in numerous opportunities for battery scientists.