A flexible, hierarchically porous PANI/MnO2 network with fast channels and an extraordinary chemical process for stable fast-charging lithium-sulfur batteries
A flexible, hierarchically porous PANI/MnO2 network with fast channels and an extraordinary chemical process for stable fast-charging lithium-sulfur batteries
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灵活的分层多孔PANI/MnO2网络，具有快速通道和非凡的化学工艺，可实现稳定的快速充电锂硫电池
DOI：
10.1039/c9ta12135h
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发表时间：
2020
影响因子：
11.9
通讯作者：
Su Bao-Lian
中科院分区：
文献类型：
--
作者：
Zhang Yunjing;Liu Xiaolin;Wu Liang;Dong Wenda;Xia Fanjie;Chen Liangdan;Zhou Na;Xia Lixue;Hu Zhi-Yi;Liu Jing;Mohamed Hemdan S. H.;Li Yu;Zhao Yan;Chen Lihua;Su Bao-Lian
具有高理论比容量的锂硫电池在储能系统中具有很好的应用前景。然而，锂硫电池的应用主要受到多硫化物在充电/放电过程中的严重穿梭效应的阻碍。在这里，我们报告的超薄柔性聚苯胺层修饰的二氧化锰纳米粒子（PANI-MnO 2）的原位自组装，形成一个三维的分层多孔网络作为硫主机的锂硫电池。分级多孔PANI-MnO 2网络不仅提供多孔结构以减轻体积膨胀，而且提供快速通道以加速活性物种、电子和离子的转移以改善氧化还原反应动力学。因此，所制备的PANI-MnO 2-S电极表现出优异的电化学性能，在0.5C下100次循环后具有高达1195 mA h g−1的稳定容量。特别是，分级多孔PANI-MnO 2网络采用了一种特殊的化学过程，使多硫化物形成活性硫代硫酸盐，并进一步转化为Li 2S。这显著抑制了穿梭效应，从而提供了快速充电的可能性。结果，PANI-MnO 2-S电极在2C下500次循环后表现出640 mA h g-1的放电容量。即使在4.0 mg cm−2的高硫负载下，在1C下经过200次循环后仍能实现稳定的面积容量1.33mA h cm−2。
Lithium–sulfur batteries with high theoretical specific capacity are quite promising in energy storage systems. The application of lithium–sulfur batteries however has mainly been hampered by the severe shuttle effect of polysulfides during the charging/discharging process. Here, we report the in situ self-assembling of ultra-thin flexible polyaniline layer decorated manganese dioxide nanoparticles (PANI–MnO2) to form a three-dimensional hierarchically porous network as a sulfur host for lithium–sulfur batteries. The hierarchically porous PANI–MnO2 network not only provides a porous structure to alleviate the volume expansion, but also offers fast channels to accelerate the transfer of active species, electrons and ions to improve the redox reaction kinetics. The as-fabricated PANI–MnO2–S electrode thus demonstrates excellent electrochemical performance, with a stable capacity up to 1195 mA h g−1 at 0.5C after 100 cycles. In particular, the hierarchically porous PANI–MnO2 network employs an extraordinary chemical process for polysulfides to form active thiosulfates, which are further converted into Li2S. This significantly suppresses the shuttle effect, thus providing the possibility for fast charging. As a result, the PANI–MnO2–S electrode exhibits a discharge capacity of 640 mA h g−1 at 2C after 500 cycles. Even at a high sulfur loading of 4.0 mg cm−2, a stable areal capacity of ∼3.12 mA h cm−2 is achieved at 1C after 200 cycles.