Li₂S-Based Li-Ion Sulfur Batteries: Progress and Prospects

The great demand for high-energy-density batteries has driven intensive research on the Li–S battery due to its high theoretical energy density. Consequently, considerable progress in Li–S batteries is achieved, although the lithium anode material is still challenging in terms of lithium dendrites and its unstable interface with electrolyte, impeding the practical application of the Li–S battery. Li₂S-based Li-ion sulfur batteries (LISBs), which employ lithium-metal-free anodes, are a convenient and effective way to avoid the use of lithium metal for the realization of practical Li–S batteries. Over the past decade, studies on LISBs are carried out to optimize their performance. Herein, the research progress and challenges of LISBs are reviewed. Several important aspects of LISBs, including their working principle, the physicochemical properties of Li₂S, Li₂S cathode material composites, LISBs full batteries, and electrolyte for Li₂S cathode, are extensively discussed. In particular, the activation barrier in the initial charge process is fundamentally analyzed and the mechanism is discussed in detail, based on previous reports. Finally, perspectives on the future direction of the research of LISBs are proposed. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim