室温钠硫电池硫化钠正极的发展现状与应用挑战

The recent progress and future opportunities of Na2S cathode for room temperature sodium sulfur batteries

室温钠硫电池以其高能量密度、资源丰富、价格低廉等优势有望在大规模储能、动力电池等领域实现广泛应用而备受青睐。其中,室温钠硫电池的放电最终产物硫化钠,可以作为正极材料,不仅理论比容量高(686 mAh/g),且可以与非钠金属负极(如硬碳、锡金属)匹配从而避免直接使用钠金属负极带来的安全隐患等优点逐渐成为研究热点。然而由于硫化钠正极材料的本征电导率低、反应活性差、与多硫化物的可逆循环差等缺点限制了其实际比容量和循环寿命。本文通过对硫化钠正极材料的工作机理深入探讨,从材料理性设计和电池结构构造的角度入手,着重讨论硫化钠正极材料本征电导性和与多硫化物的可逆循环性的提升策略,并重点介绍了硫化钠正极材料的近期研究进展。最后,面向硫化物正极材料的实际化应用需求,凝练出推动其进一步发展的重要研究方向。

Room temperature sodium sulfur batteries are regarded as the next generation of large-scale energy storage systems because of its high energy density and the abundant resources of sodium and sulfur.Na_(2)S is a promising cathode material that possesses a high theoretical capacity(686 mAh/g),and is able to be coupled with non-sodium metal anode(e.g.,hard carbon or Sn),which can get rid of the safety issues related to sodium metal.However,the electronically insulating nature and the poor reactivity of Na_(2)S,and its low kinetics conversion to polysulfides result in a large first-charge overpotential and poor cycle life,limiting their practical application.Herein,the fundamental knowledge and principle of storage sodium of Na_(2)S is detailed discussed.Additionally,recent reports on enhanced electrochemical performance strategies are comprehensively reviewed in detail with an emphasis on carbon-based Na_(2)S composite materials,Na_(2)S morphological structure design,Na_(2)S electrocatalytic mechanism,and device design.Finally,the perspectives are proposed on the future opportunities for Na_(2)S cathode material that are obstructing more practical Na_(2)S cathode based batteries.