原位固化抑制锂硫电池中可溶性多硫化物的研究

Inhibition of soluble polysulfide in Li-S batteries by in situ solidification

电池是制约新能源汽车快速发展的关键问题之一,新能源汽车对电池最大的要求在于储能。锂硫(Li-S)电池由于其能量密度高、成本低,在新能源汽车下一代储能系统中脱颖而出。但多硫化物(LiPSs)溶解和穿梭问题导致严重的性能下降,阻碍电池在新能源汽车的实际应用。通过电解液中的对二氯苯(PDCB)引发亲核取代反应使多硫化物有效地固定在正极内,有助于保持高容量。LiPSs-PDCB复合物具有更低的带隙,能够促进硫氧化还原反应动力学,且使用PDCB后,Li-S电池在0.1 C时表现出1 216 mAh/g的大初始比容量。1 C下130次稳定循环,剩余比容量为690mAh/g,具有优异的电化学性能。

Battery is one of the key problems restricting the rapid development of new energy vehicles.The biggest requirement of battery for new energy vehicles is energy storage.Lithium-sulfur(Li-S)batteries stand out among nextgeneration energy storage systems for new energy vehicles due to their high energy density and low cost.However,polysulfide(LiPSs)dissolution and shuttle problems lead to serious performance degradation,hindering the practical application in new energy vehicles.A nucleophilic substitution reaction initiated by p-dichlorobenzene(PDCB)in the electrolyte was proposed to effectively immobilize polysulfide in the positive electrode,thus helping to maintain high capacity.In addition,the LIPSS-PDCB complex had a lower band gap and is able to promote the kinetics of sulfur REDOX reactions,while the LI-S cell exhibitd a large initial capacity of 1216 mAh/g at 0.1 C after PDCB use.130 stable cycles at 1 C with a residual capacity of 690 mAh/g indicated excellent electrochemical performance.