High power all solid state batteries using sulfide superionic conductors
Compared with lithium ion batteries with liquid electrolytes, all solid state batteries offer an attractive option owing to their potential in improving the safety and achieving both high power and high energy densities. Despite extensive research efforts, the development of all solid state batteries still falls short of expectation largely because of the lack of suitable candidate materials for the electrolyte required for practical applications. Here we report lithium superionic conductors with an exceptionally high conductivity (25 mS cm 1 for Li9.54Si1.74P1.44S11.7Cl0.3) as well as high stability ~0 V versus Li metal for Li9.6P3S12) A fabricated all solid state cell based on this lithium conductor is found to have very small internal resistance, especially at 100 C. The cell possesses high specific power that is superior to that of conventional cells with liquid electrolytes. Stable cycling with a high current density of 18 C (charging/discharging in just three minutes; where C is the C rate) is also demonstrated. The development of all solid state batteries requires fast lithium conductors. Here, the authors report a lithium compound, Li9.54Si1.74P1.44S11.7Cl0.3, with an exceptionally high conductivity and demonstrate that all solid state batteries based on the compound have high power densities.