Lithium sulfur flow battery with 250 Wh/L energy density


From pv magazine Global

Edinburg-based startup StorTera has developed a single liquid flow battery (SLIQ), which is a a novel, long-duration renewable energy storage system. It combines the advantages of lithium-ion technology – namely, high energy density and rapid response – with the benefits of flow batteries, such as a lower levelized cost of storage.

“By combining the concepts, we have overcome the inherent shortcomings of lithium sulfur battery which have prevented it from being successfully commercialized at scale,” StorTera COO Brenda Park told pv magazine.

With an energy density of 250 Wh/L, the SLIQ is touted as the most energy dense flow battery now under development.

“Due to its high energy density, the SLIQ can replace existing lithium technology in any many applications while providing a much longer lifetime (up to 30 years) with minimal degradation of efficiency,” said Park.

The technology purportedly provides millisecond response times and up to eight hours of energy storage for more than 20 years and a minimum of 7,500 cycles. The system is said to offer improved safety with no cooling requirements and high flash point materials.

“We are striving to make this a truly sustainable battery technology, building a circular economy around it using recovered or recycled raw materials where possible and by making it as reusable as possible,” said Park.

StorTera’s system works by pumping energy-dense single liquid through its proprietary membrane stack to provide long-duration storage. The single liquid design means less system components, whereas low-cost materials and manufacturing techniques further contribute to cost savings. StorTera has a stated goal of reaching capital costs of approximately GBP 120 ($146.20)/kW and GBP 75/kWh when commercialized.

“As it can provide both millisecond response time and long duration energy storage, it is well suited to grid scale applications and/or integration with solar or wind farms,” Park said. “Combined with our intelligent control platform, the SLIQ offers distinct advantages to commercial and industrial applications where it can be optimized continuously according to grid and weather data or by predicting demand peaks.”

In late November, StorTera secured about GBP 5 million from the UK government to help build a large-scale, eight- hour demonstrator of the SLIQ, which will be installed in Edinburgh in 2024. The prototype SLIQ will use a novel cylindrical cell architecture in a modular format to optimize the manufacture, installation, and maintenance of the system.

With a focus on sustainability, the system will use recyclable materials and by-products of the wood industry. Toward the end of the project, eight modular units will be combined to build a 200 kW/1.6 MWh demonstrator SLIQ.

“While developing the SLIQ, we have been providing bespoke small and medium scale lithium ferro phosphate (LFP) battery systems integrated with our intelligent platform to public sector, domestic and commercial customers in the UK. We have also piloted innovative smart grids in the UK and Canada that show the benefits that intelligent energy storage can offer to customers,” Park said. “Our commercial projects are paving the way for the SLIQ when it is commercialized in the next few years.”

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