Bimodal highly ordered mesostructure carbon with high activity for Br2/Br? redox couple in bromine based batteries

By Chenhui Wang and Xianfeng Li and Xiaoli Xi and Wei Zhou and Qinzhi Lai and Huamin Zhang
Published in Nano Energy NULL 2016

Abstract

Bimodal highly ordered mesostructure carbons (BOMCs) with excellent activity to Br2/Br? were designed and fabricated by an evaporation induced triconstituent co-assembly method. The morphologies of \BOMCs\ were tuned via introducing dual templates: triblock copolymer (F127) and SiO2 nanoparticles, where around 5 nm pores can be induced by hydrogen bond between resole and \F127\ and the removal of silica could create around 2 nm pores on the 5 nm pore walls. The highly ordered mesostructure can effectively shorten mass transfer distance and reduce mass transfer resistance. Meanwhile the around 2 nm pores on 5 nm pore walls are beneficial to Br2 adsorption and provide more active sites to Br2/Br? reaction. As a consequence, the materials demonstrate extremely outstanding performance to Br2/Br? couple. The zinc bromine flow batteries (ZBFBs) using the prepared carbon exhibit a voltage efficiency of 82.9% and an energy efficiency of 80.1% at the current density of 80 mA cm?2, which is by far the best performance ever reported, confirming the excellent activity of designed materials. The results indicate that the prepared \BOMC\ with bimodal highly ordered mesostructure is a very promising candidate for bromine based batteries systems.

Read Article » Back