Free-standing TiO2 nanowire-embedded graphene hybrid membrane for advanced Li/dissolved polysulfide batteries
Free-standing TiO2 nanowire-embedded graphene hybrid membrane for advanced Li/dissolved polysulfide batteries
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DOI：
10.1016/j.nanoen.2014.12.029
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发表时间：
2015-03
期刊：
影响因子：
17.6
通讯作者：
Guangmin Zhou;Yubao Zhao;Chenxi Zu;A. Manthiram
中科院分区：
文献类型：
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作者：
Guangmin Zhou;Yubao Zhao;Chenxi Zu;A. Manthiram
电动汽车和大规模智能电网的需求日益增长，引起了人们对开发高能量密度存储设备的极大兴趣。锂硫（Li-S）电池因其高理论能量密度和丰富的资源而备受关注，但容量衰减快、硫负载量和利用率低等问题阻碍了其实际应用。在这里，我们提出了一个独立的TiO 2纳米线/石墨烯杂化膜的锂/溶解多硫化物电池具有高容量和长循环寿命。采用具有高导电性的石墨烯膜作为集流体，有效降低硫阴极中的内阻，并对溶解的多硫化锂进行物理包覆。引入石墨烯膜中的TiO 2纳米线提供了一种分级复合结构，其中TiO 2纳米线不仅与多硫化锂有很强的化学键合，而且对多硫化锂的还原和氧化表现出很强的催化作用，促进了快速的氧化还原反应动力学，具有高容量和低电压极化。该复合电极在0.2 C倍率下的比容量高达1327 mA h g− 1，库仑效率接近100%，高倍率性能为850 mA h g− 1（2 C倍率），长循环稳定性为1053 mA h g− 1（200次循环），在高能锂硫电池中具有良好的应用前景。
The increasing demand for electric vehicles and large-scale smart grids has aroused great interest in developing high energy density storage devices. Lithium–sulfur (Li–S) battery has attracted much attention owing to its high theoretical energy density and abundance, but many challenges such as rapid capacity fade and low sulfur loading and utilization have impeded its practical use. Here, we present a free-standing TiO2nanowire/graphene hybrid membrane for Li/dissolved polysulfide batteries with high capacity and long cycling life. Graphene membrane with high electrical conductivity is used as a current collector to effectively reduce the internal resistance in the sulfur cathode and physically immobilize the dissolved lithium polysulfides. The TiO2nanowires introduced into the graphene membrane offer a hierarchical composite structure, in which the TiO2nanowires not only have strong chemical binding with the lithium polysulfides, but also show a strong catalytic effect for polysulfide reduction and oxidation, promoting a fast redox reaction kinetics with high capacity and low voltage polarization. This hybrid electrode delivers a high specific capacity of 1327 mA h g−1at 0.2 C rate, a Coulombic efficiency approaching 100%, high-rate performance of 850 mA h g−1at 2 C rate, and long cyclic stability with a capacity of 1053 mA h g−1at 0.2 C rate over 200 cycles, demonstrating great prospect for application in high energy Li–S batteries.