Researchers in UCLA Department of Chemistry and Biochemistry and Department of Material Science Engineering have developed an electrocatalytic strategy to eliminate polysulfide shuttling and significantly improve Lithium-Sulfur (Li-S) battery performance.
Lithium-sulfur (Li-S) chemistry has gained research interest as a promising next-generation lithium battery cathode material, with a theoretical energy density of 2600 Wh/kg. However, fundamental challenges facing Li–S batteries are: the insulating properties of sulfur and its reduced products, the pulverization of the cathode and the polysulfide shuttling (soluble lithium polysulfides, LiPS), impeding the practical performance. Current methods have used mesoporous carbon to overcome the insulating properties and trapping LiPS but these methods still lead to a dramatic capacity loss and low utilization of active materials. There is a need for new methods to mechanistically catalyze the polysulfide intermediates to improve reaction chemistry and maximize the practical performance and battery life of Li-S.
UCLA researchers from have developed a catalytic sulfur reduction reaction (SRR) method that rapidly catalyzes polysulfide consumption upon generation, to improve Li-S battery performance. The method has been successfully tested to lower the activation energy of SRR from 0.26 eV to 0.06 eV, allowing for the fast consumption of any existing polysulfides that insulate and reduce capacitance of active material. The method has a much-improved rate capability and cycling stability, with a high capacity of 590 mAh/g at 2C and an ultralow capacity decay of 0.015%/cycle at 1C for 500 cycles. The prototype cathode can uphold an active mass up to 8 mg/cm2, and still delivers superior capacity retention of 97% at 0.1 C after 100 cycles.
A successful demonstration of the reduction reaction has been performed.
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