Catalytic Immobilization of Sulfur for High-performance Room-temperature Sodium-Sulfur Batteries

Room-temperature sodium-sulfur (RT-Na/S) batteries are among the ideal candidates to meet the scale and cost requirements of the market due to their overwhelming advantages: the high theoretical capacity of S (1672 mAh g-1), and its low cost, non-toxicity, and resource abundance. Nevertheless, RT-Na/S batteries are facing critical problems with respect to low reversible capacity and fast capacity fade. The sluggish reactivity of S with Na, resulting in incomplete reduction to Na2Sx (x ≥ 2), rather than complete reduction to Na2S, is the main reason for their low accessible capacity; their fast capacity fade is due to the dissolution of long-chain polysulfides in the electrolyte, which leads to the rapid loss of active materials.