Curtailing Carbon Usage with Addition of Functionalized NiFe2O4 Quantum Dots: Toward More Practical S Cathodes for Li–S Cells
Ning Li, Ting Meng, Lai Ma, Han Zhang, JiaJia Yao, Maowen Xu, Chang Ming Li, Jian Jiang
Abstract
Abstract Smart combination of manifold carbonaceous materials with admirable functionalities ( like full of pores/functional groups, high specific surface area) is still a mainstream/preferential way to address knotty issues of polysulfides dissolution/shuttling and poor electrical conductivity for S-based cathodes. However, extensive use of conductive carbon fillers in cell designs/technology would induce electrolytic overconsumption and thereby shelve high-energy-density promise of Li–S cells. To cut down carbon usage, we propose the incorporation of multi-functionalized NiFe 2 O 4 quantum dots (QDs) as affordable additive substitutes. The total carbon content can be greatly curtailed from 26% (in traditional S/C cathodes) to a low/commercial mass ratio (~ 5%). Particularly, note that NiFe 2 O 4 QDs additives own superb chemisorption interactions with soluble Li 2 S n molecules and proper catalytic features facilitating polysulfide phase conversions and can also strengthen charge-transfer capability/redox kinetics of overall cathode systems. Benefiting from these intrinsic properties, such hybrid cathodes demonstrate prominent rate behaviors (decent capacity retention with ~ 526 mAh g −1 even at 5 A g −1 ) and stable cyclic performance in LiNO 3 -free electrolytes (only ~ 0.08% capacity decay per cycle in 500 cycles at 0.2 A g −1 ). This work may arouse tremendous research interest in seeking other alternative QDs and offer an economical/more applicable methodology to construct low-carbon-content electrodes for practical usage.