Li Ning, Meng Ting, Ma Lai, Zhang Han, Yao JiaJia, Xu Maowen, Li Chang Ming, Jiang Jian
School of Materials and Energy, and Chongqing Key Lab for Advanced Materials and Clean Energies of Technologies, Southwest University, No. 2 Tiansheng Road, BeiBei District, Chongqing, 400715, People's Republic of China.
School of Physical Science and Technology, Southwest University, No. 2 Tiansheng Road, BeiBei District, Chongqing, 400715, People's Republic of China.
Nanomicro Lett. 2020 Jul 11;12(1):145. doi: 10.1007/s40820-020-00484-4.
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 NiFeO 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 NiFeO QDs additives own superb chemisorption interactions with soluble LiS 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 even at 5 A g) and stable cyclic performance in LiNO-free electrolytes (only ~ 0.08% capacity decay per cycle in 500 cycles at 0.2 A g). 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.
将具有令人钦佩功能(如充满孔隙/官能团、高比表面积)的多种碳质材料进行巧妙组合,仍然是解决多硫化物溶解/穿梭以及硫基阴极导电性差等棘手问题的主流/首选方法。然而,在电池设计/技术中大量使用导电碳填料会导致电解液过度消耗,从而搁置锂硫电池的高能量密度前景。为了减少碳的使用,我们提出引入多功能化的NiFeO量子点(QDs)作为经济实惠的添加剂替代品。总碳含量可以从26%(传统硫/碳阴极中)大幅降低到较低的/商业质量比(约5%)。特别要注意的是,NiFeO量子点添加剂与可溶性LiS分子具有极好的化学吸附相互作用以及促进多硫化物相转化的适当催化特性,并且还可以增强整个阴极系统的电荷转移能力/氧化还原动力学。受益于这些固有特性,这种混合阴极在无LiNO电解液中表现出突出的倍率性能(即使在5 A g下仍有526 mAh g的良好容量保持率)和稳定的循环性能(在0.2 A g下500次循环中每循环仅0.08%的容量衰减)。这项工作可能会激发在寻找其他替代量子点方面的巨大研究兴趣,并为构建用于实际应用的低碳含量电极提供一种经济/更适用的方法。