Scaled Electricity Storage Using Lithium-Sulfur Batteries

The University of St Andrews and OXIS Energy Ltd will collaborate in order to demonstrate a lithium-sulfur (Li-S) flow
battery. Li-S chemistry has two key advantages; it uses cheap and abundant raw materials; and delivers vastly improved
energy density in comparison to incumbent technologies. Li-S batteries are therefore cheaper per unit of energy stored
than incumbent technologies. The proposed project will seek to demonstrate how this can be exploited together with a
novel Redox Flow Battery (RFB) design to deliver cost effective energy storage at a grid level. The project will demonstrate
the operation of a lab scale Li-S RFB. This will involve the design and construction of new test hardware; the development
of new electrolyte formulations; the testing of novel electrode materials and composites; and finally the investigation of
operation conditions. The resulting battery will establish the commercial feasibility of the concept for stationary applications,
where large battery capacity and low cost are essential. This inexpensive grid-scale battery promises to efficiently connect
intermittent renewables to the grid thus increasing energy security while simultaneously reducing both bills and emissions.

This project seeks to advance energy storage technologies by testing the feasibility of a potentially disruptive new grid
storage technology. We will work with OXIS Energy Ltd to evaluate electrolyte formulations, electrode materials and modes
of operation for a lithium-sulfur flow battery.
With regards to the energy trilemma, the benefits of energy storage are difficult to quantify as its impact on cost, security,
and emissions are all interrelated. This is made more difficult by the complexity our energy networks. However, the most
comprehensive attempt has been made, on behalf of the Carbon Trust, by Strbac et al (1). This work creates a whole
system model of the UK's energy network built on "pathways" developed by DECC in their "Carbon Plan". The pathways
are essentially visions of how the governments CO2 emission and energy security targets can be met. The model is then
used to calculate how much electrical storage would minimise the systems total costs and what those costs would be. For
example for a "pathway" high in renewable energy, and with a similar storage cost as is expected for this technology
(<£100 / kW.year), the model predicts that CO2 emission could be reduced by 50% (1950 MtCO2eq), while also
maintaining the UKs energy security, by deploying 14.8GW (24hrs) of storage.
The model estimates that this would produce savings of £2bn p.a. in comparison to a similar system with no energy
storage. While this might not represent our true energy future it does provide strong evidence that energy storage, such as
that proposed by this project, offers significant benefits.
Energy storage is shown to; reduce overall costs to those involved in generation, transmission and distribution; minimise
consumer's energy bills; increase the UK's energy independence; and mitigate the effects of global warming for all, by
reducing CO2 emissions.
OXIS will benefit by exploring a nascent field which has the potential to both enhance their existing technology and open up
a potentially large new market in a related area. USTAN will benefit by cementing its reputation for world class energy
storage research and by helping to establish a new high technology business. The UK may ultimately benefit from new high
value manufacturing jobs and the export of technology.
(1) G.Strbac, M.Aunedi, D.Pudjianto, P.Djapic, F.Teng, A.Sturt, D.Jackravut, R.Sansom, V.Yufit and N.Brandon, "Strategic
Assessment of the Role and Value of Energy Storage Systems in the UK Low Carbon Energy Future", Carbon Trust, June,
(2012).