Abstract
The shuttling diffusion of polysulfides is a bottleneck that seriously limits the performance of Li-S batteries.Purposeful construction of sulfur cathodes with reliable trapping ability of polysulfides is the key to over-come such limitation.Herein,a hierarchical porous archi-tecture,i.e.,Co(OH)2 sheets bonded Ti3C2Tx MXene aerogel(Co(OH)2/MXA),is constructed via a facile self-assembled approach and used as an efficient free-standing polysulfides reservoir.The interconnected three-dimen-sional(3D)porous network with void space and strong interfacial interaction not only enables high sulfur loading but facilitates fast ion and electron transport.Experimental and theoretical results confirm the hetero-framework exhibits outstanding immobilization and conversion ability for polysulfides due to its polar surface and bifunctional catalytic activities toward both formation and decomposi-tion of Li2S.The optimized Co(OH)2/MXA cathode delivers excellent rate capability(407 mAh·g-1 at 5C)with a sulfur loading of 2.7 mg·cm-2,and ultra-stable cycling performance as an extremely small capacity decay of～0.005％per cycle within 1700 cycles at 1C is achieved with a high sulfur loading of 6.7 mg·cm-2.More signifi-cantly,our design structural/componential methodology here promises the MXene-based aerogel electrodes for Li-S batteries and beyond.
万方数据