The DICP research group headed by Prof. Huamin Zhang and Prof. Xianfeng Li from Energy Storage Division (DNL 17) recently made a new progress in non-fluorinated porous ions conducting membranes for flow battery. This work had been published online by Angew. Chem. Int. Ed. 55， 2016， 3058-3062.
In the past few years, this research group has broken through the traditional restriction from ions exchange mechanism and proposed the concept of ions sieve-conducting mechanism (Energy Environ. Sci., 2011, 4, 1676). Based on this idea, they first introduced porous ions conducting membranes in the flow battery application and achieved significantly progresses in the non-fluorinated porous ions conducting membranes (Energy Environ. Sci., 2015, DOI: 10.1039/C5EE02896E; Energy Environ. Sci., 2013, 6, 776; Energy Environ. Sci., 2012, 5, 6299; Energy Environ. Sci., 2011, 4, 1147; Energy Environ. Sci., 2013, 6, 776; Adv. Funct. Mater., 2015, 25, 2583; Adv. Funct. Mater., 2016, 26, 210-218).
The Research Progress in Non-fluorinated Ion Conducting Membranes for Flow Battery (Photo by YUAN Zhizhang)
After many years’ research work, they found that one of the biggest challenges for flow battery applications is the transport mechanism of ions through the membranes, since the pores of currently explored membranes are normally asymmetric, curving and poor connecting, which makes it difficult to confirm the pore size exclusion directly. Thus how to preparing membranes with proper pore size in between the protons (H3O+ <0.24 nm) and vanadium ions (>0.6 nm) becomes one of the most critical issues for porous membranes. ZSM-35 zeolite, a class of crystalline aluminosilicates, owns the features of appropriate pore size (0.42 nm × 0.54 nm for 10-ring apertures and 0.35 nm × 0.48 nm for 8-ring apertures), which is in the range between the stokes radius of protons and hydrated multivalent vanadium ions, holds potential for applications in flow batteries applications. A battery assembled with this zeolite/porous membrane shows an energy efficiency over 81% at 200mA/cm2. This work is of importance for the vanadium flow battery technology, but also for the membrane technology field.
This work is financially supported by National Natural Science Foundation of China, Outstanding Young Scientist Foundation CAS and Collaborative Innovation Center of Chemistry for Energy Materials.（Text/Photo by YUAN Zhizhang)