Centro de Química da Universidade do Minho

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Mesoporous poly(vinylidene fluoride-co-trifluoroethylene) membranes for lithium-ion battery separators

Publication . Costa, C. M.; Kundu, Manab; Dias, J. C.; Nunes-Pereira, João; Botelho, Gabriela; Silva, M. M.; Lanceros-Mendez, Senentxu

Mesoporous separator membranes based on poly(vinylidene fluoride-co-trifluoroethylene), PVDF-TrFE, were prepared through the removal of ZnO nanoparticles from the polymer matrix composite. Different filler concentrations were used, and the evaluation of the morphology, mechanical properties, uptake and ionic conductivity of the membranes were demonstrated that they depend on initial ZnO content in the composite. On the other hand, the vibration peaks characteristics of PVDF-TrFE and the thermal properties are independent on initial filler content. The membrane with the best ionic conductivity, 1.6 mS/cm, is the one prepared after 70 wt.% ZnO removal. The separator membranes were assembled in Li/C-LiFePO4 half-cells exhibiting good rate capability and cycling performance, the best battery performance being obtained for the PVDF-TrFE after 70 wt.% ZnO removal. The good performance of the developed separators was also demonstrated in full battery cells. Thus, a way to tailor membrane mesoporosity is presented and it is shown that the obtained membranes represent suitable separators for lithium-ion battery applications.

2019Journal article

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Synthetic polymer-based membranes for lithium-ion batteries

Publication . Martins, Pedro; Nunes-Pereira, João; Lanceros-Mendez, Senentxu; Costa, C. M.

Efficient energy storage systems are increasingly needed due to advances in portable electronics and transport vehicles, with lithium-ion batteries standing out among the most suitable energy storage systems for a large variety of applications. In lithium-ion batteries, the porous separator membrane plays a relevant role as it is placed between the electrodes, serves as a charge transfer medium, and affects the cycle behavior. Typically, porous separator membranes are comprised of a synthetic polymeric matrix embedded in the electrolyte solution. The present chapter focus on recent advances in synthetic polymers for porous separation membranes as well as on the techniques for membrane preparation and physicochemical characterization. The main challenges to improve the synthetic polymer performance for battery separator membrane applications are also discussed.

2020Book part

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