Defect-riched prussian blue analogues with superior adsorption-catalysis toward lithium polysulfides for high performance lithium-sulfur batteries

Lithium-sulfur batteries (Li-S) garner significant interest within the energy storage industry, because of their exceptional theoretical energy density coupled with employment of environmental materials. Nevertheless, the broader implementation of Li-S batteries faces challenges, primarily due to the lithium polysulfide (LiPSs) shuttle effect and the sluggish conversion kinetics associated with LiPSs. In this work, we introduce a reduction- induced dissolution process to fabricate a mesoporous CoFePB rich in crystal defects via a facile solvothermal method. The experimental results indicate that the abundance of crystal defects originate from the phase transition from Co3[FeIII(CN)6]2 to Co2[FeII(CN)6]. The subsequent adsorption tests and electrochemical evaluations have shown that the defect-rich CoFePB possesses enhanced LiPSs absorption capacity and improved cycling performance in contrast to the pristine CoFePB, which is primarily ascribed to proliferation of active sites emerging as a result of the crystal defects. Consequently, the D-CoFePB-S cathode demonstrates remarkable rate performance with 583 mAh g- 1 at a substantial 5C current rate, superior long-term stability with capacity retention of 64.3 % over 2000 cycles at current rate of 2C and outstanding areal capacity of 4.9 mAh cm- 2 at 0.1C, even under a substantial sulfur loading of 5.0 mg cm- 2 .