锂硫电池中氧化还原反应涉及复杂的多相转化过程,对其性能至关重要.催化转换是缓解穿梭效应的有效策略,但单组分催化剂在双向氧化还原过程中并不能充分发挥作用.为此,我们制备了一维ZnO@NiO核-壳纳米带(CNBs),通过p-n结界面来解决这些问题.自发内置电场(BIEF)诱导界面电荷重新分配,促进了ZnO和NiO之间的电荷和多硫化物的转移.适度的吸附能和多硫化物转化能垒的降低进一步加速了硫的双向转化.ZnO@NiO CNBs阴极在0.1 C下的放电容量为1525.5 mA hg-1,在2 C下循环1000次后,保持了73.60％的容量保持率,相当于每循环损失0.026％的容量.本研究证明了BIEF和异质结构的结合促进了多硫化物的转化,为调控多硫化物氧化还原反应提供了新策略.
Promoting polysulfide bidirectional conversion by one-dimensional p-n junctions for Li-S batteries
Sulfur redox reactions are crucial in lithium-sulfur(Li-S)batteries,typically characterized by intricate multiphase conversion processes.A catalytic approach to transform polysulfides effectively mitigates the shuttle effects in Li-S batteries.However,a catalyst consisting of a single component cannot fully participate in the two-way redox process.In this study,we have addressed these issues by fab-ricating one-dimensional ZnO@NiO core-shell nanobelts(CNBs),which establish a p-n junction interface.A built-in electric field(BIEF)at this interface results in the spontaneous redistribution of charges,facilitating the transfer of electrons between the ZnO and NiO surfaces.While this weakens the strong adsorption properties,it simultaneously expedites the transfer of polysulfide.As a result of the moderate adsorption capacity of polysulfide and the lowered energy barrier for sulfur conversion,the intrinsic catalytic activity of ZnO@NiO p-n junctions contributes to the increased speed of bidirec-tional sulfur conversion.The as-prepared cathode,composed of ZnO@NiO CNBs,demonstrates an outstanding discharge capacity of 1525.5 mA h g-1 at a rate of 0.1 C.Following 1000 cycles at a rate of 2 C,the ZnO@NiO CNBs cathode maintains a substantial capacity,with a retention rate of 73.60％,equivalent to an impressively low capacity loss of 0.026％per cycle.This research highlights the synergy of the BIEF and heterostructures in facilitating the gradual transport of poly-sulfides,offering new perspectives on designing interfacial structures for the controlled regulation of polysulfide redox reactions.
Henan International Joint Laboratory of MXene Materials Microstructure,School of Physics and Electronic Engineering,Nanyang Normal University,Nanyang 473061,China
Engineering Research Center for MXene Energy Storage Materials of Henan Province,School of Physics and Electronic Engineering,Xinyang Normal University,Xinyang 464000,China
School of Chemistry and Chemical Engineering,Yangzhou University,Yangzhou 225002,China
NETL
NSTL
万方数据
