Recent progress in Li-S and Li-Se batteries

Li-S and Li-Se batteries have attracted tremendous attention during the past several decades, as the energy density of Li-S and Li-Se batteries is high (several times higher than that of traditional Li-ion batteries). Besides, Li-S and Li-Se batteries are low cost and environmental benign. However, the commercial applications of Li-S and Li-Se batteries are hindered by the dissolution and shuttle phenomena of polysulfide (polyselenium), the low conductivity of S (Se), etc. To overcome these drawbacks, scientists have come up with various methods, such as optimizing the electrolyte, synthesizing composite electrode of S/polymer, S/carbon, S/metal organic framework (MOF) and constructing novelty structure of battery. In this review, we present a systematic introduction about the recent progress of Li-S and Li-Se batteries, especially in the area of electrode materials, both of cathode material and anode material for Li-S and Li-Se batteries. In addition, other methods to lead a high-performance Li-S and Li-Se batteries are also briefly summarized, such as constructing novelty battery structure, adopting proper charge-discharge conditions, heteroatom doping into sulfur molecules, using different kinds of electrolytes and binders. In the end of the review, the developed directions of Li-S and Li-Se batteries are also pointed out. We believe that combining proper porous carbon matrix and heteroatom doping may further improve the electrochemical performance of Li-S and Li-Se batteries. We also believe that Li-S and Li-Se batteries will get more exciting results and have promising future by the effort of battery community.