A versatile nano-TiO2 decorated gel separator with derived multi-scale nanofibers towards dendrite-blocking and polysulfide-inhibiting lithium-metal batteries
A versatile nano-TiO2 decorated gel separator with derived multi-scale nanofibers towards dendrite-blocking and polysulfide-inhibiting lithium-metal batteries
In this study,a versatile fluorine-bearing gel membrane with multi-scale nanofibers was rationally designed and synthesized via facile one-step blend electrospinning of nano-titanium dioxide(TiO2)par-ticles and fluorinated poly-m-phenyleneisophthalamide(PMIA)polymer solution.The prepared multi-scale TiO2-assisted gel separator presented relatively high porosity,small aperture,giving rise to superior affinity to electrolyte and sufficient active sites to accelerate lithium ions migration.Meanwhile,the as-fabricated multifunctional GPE also rendered outstanding heat-resistance and well-distributed lithium-ions flux,and the mutual overlaps between the coarse fibers and the fine fibers within the multi-scale nanofiber membrane provided a strong skeleton support,which in turn laid a solid footing stone for high-security and dendrite-proof batteries.Particularly,the nano-TiO2 particles within PMIA membrane acted as"gatekeepers",which can not only resist the growth of lithium dendrites,but also intercept the dissolved polysulfide on cathode side.Based on these merits,the gel PMIA-based lithium cobalt(LCO)/lithium battery obtained the remarkably improved rate capability and cycle performances on account of superior ionic conductivity,steady anodic stability window and weakened polarization behavior.Meanwhile,the resultant lithium-sulfur cell also delivered the outstanding cycling stability with the aid of the greatly prevented"shuttle effect"of dissolved lithium polysulfides based on the physical trap-ping and chemical binding of the prepared GPE to polysulfides species.This work proved that the addition of functional inorganic nanoparticles similar with TiO2 in multi-scale gel PMIA membrane can enhance the lithium ions transport capability,resist the growth of lithium dendrites as well as inhibit the shuttle effect of polysulfides,which would prompt a great development for dendrite-blocking and polysulfide-inhibiting lithium-metal cells.
A versatile nano-TiO2 decorated gel separator with derived multi-scale nanofibers towards dendrite-blocking and polysulfide-inhibiting lithium-metal batteries