Thermodynamic analysis and perspective of aqueous metal-sulfur batteries

With technical challenges and great opportunities, aqueous metal-sulfur batteries (AMSBs) are born in response to the great demand of growing electric vehicle industry. In this paper, the quantitative analysis on thermodynamic calculations of 316 systems is performed for AMSBs and 63 Eh-pH diagrams (Pourbaix-diagram) as the qualitative references are also presented, aiming to confirm the certainly technical barriers, to illustrate the working mechanisms, and to choose promising battery systems. On the basis of thermodynamic calculations, energy storage mechanism, energy density, standard electrode potential, specific capacity, volume changes of electrode materials, chemical stability of metal anodes, and chemical stability of discharge products in AMSBs are analyzed and discussed systematically. In addition, security risks, kinetic issues, and practical applications are discussed and the challenges from aqueous electrolyte are also analyzed to introduce AMSBs more comprehensively. Finally, some promising metal-sulfur systems are proposed according to the joint analysis of thermodynamic calculations and practical conditions.