Flexible hierarchically PANI/MnO2 porous network with fast channels and extraordinary chemical process for stable fast-charging lithium-sulfur battery
Lithium-sulfur batteries with high theoretical specific capacity are quite promising in the energy storage systems. The application of lithium-sulfur batteries however has mainly been hampered by the severe shuttle effect of polysulfides in the process of discharging/charging. Here, we report in-situ self-assembling ultra-thin flexible polyaniline decorating manganese dioxide nanoparticle (PANI-MnO2) to form a three-dimensional (3D) hierarchically porous network as sulfur host for lithium-sulfur battery. The hierarchically porous PANI-MnO2 network not only provides the porous structure to alleviate the volume expansion, but also offer fast channels to accelerate the transfer of active species, electrons and ions to improve the redox reaction kinetics. The as-fabricated PANI-MnO2-S composite thus demonstrates excellent electrochemical performance, with a stable capacity up to 1164 mA h·g-1at 0.5 C after 100 cycles. In particular, the hierarchically porous PANI-MnO2 network employs extraordinary chemical process with polysulfides to form active thiosulfates, which are further converted into Li2S. This significantly suppresses the shuttle effect, thus provides the possibility for fast charging. As a result, the PANI-MnO2-S electrode exhibits the discharge capacity of 622 mA h·g-1 at 2 C after 500 cycles.