Zeolite makes for a better battery life (Day 291)
14th March 2015
And now it seems that applications of zeolite stretches even further - today's blog focuses on the use of crystalline zeolite membranes to extend battery life for renewable power systems.
Smart grids, along with renewable solar and wind power systems, require affordable and efficient energy storage batteries. The reason for this is rather obvious - renewable energy sources such as wind and solar are intermittent. Also, there is a need to balance supply and demand.
But the current high cost and short life span of storage batteries are preventing widespread market penetration and economic viability of these renewable systems.
Research led by Junhang Dong, professor of chemical engineering at the University of Cincinnati, US, addresses this issue twofold.
First, Junhang has shown that the use of crystalline zeolite membranes improves the stability of the ion transfer process within the battery.
And second, by gaining a fundamental understanding of this ion transfer process, Junhang can better define the problem and therefore design materials that could deliver a high performance storage battery.
Current ion exchange membranes are typically flexible, polymer based materials that eventually break down. But Junhang's findings could lead to a more robust, high performance redox flow battery (RFB) at lower cost and with a longer service life.
Junhang found that the pore openings in the zeolite material are big enough to allow for the necessary transfer of metallic ions, but small enough to prevent the transfer of larger hydrogen and oxidative molecules to the separating membrane inside the battery.
Junhang's research looks closely at why zeolite's rigid structure and sub-nanometre pores can effectively discriminate between molecules that can fit through its entrance and those that can’t.
Zeolite differs from conventional polymeric membranes, it has crystalline solid oxide molecular sieves with a rigid, non-swollen framework. This produces a much stronger resistance to oxidants and acids.
Working with his chemical engineering PhD students and undergraduates, Junhang published the groups' findings in the Chemical Communications journal titled; Zeolite ion exchange membrane for redox flow battery.
“We are presently focusing on developing new types of ion exchange membranes. In particular, membranes of nanoporous zeolitic materials that are the key elements in the flow battery’s system,” says Junhang.
He continued: “To do this we must better understand the mechanisms of ion diffusion or conduction in the zeolitic channels and the factors controlling the ion transport behaviour so we can optimize the membrane material and take this technology to the next level and improve the battery’s performance.
“We ultimately hope to make a positive impact on society, industry and the economy by helping to develop a more prevalent, efficient and affordable battery for the fast growing renewable energy industry.”
The novel use of crystalline zeolite membranes in redox flow batteries has the potential to provide the most affordable option for large-scale electrical energy storage.
It is clear to see from today's blog, and indeed many previous posts (see 'Add just a pinch of salt for longer battery life', 'The next generation of ultra-fast charging batteries' and 'Bulletproof batteries'), that chemical engineering matters when it comes to cracking the energy storage challenge.