Periodic Reporting for period 2 - SEED (Solvated Ions in Solid Electrodes: Alternative routes toward rechargeable batteries based on abundant elements)
Reporting period: 2021-12-01 to 2023-05-31
Since its commercialization in 1991, the lithium-ion battery technology is a real success story. Costs have been dramatically reduced and the energy density increased from less than 100 Wh/kg to almost 300 Wh/kg today. On the other hand, the technology is expected to reach its physical limits within the next years. At the same time, the demand for LIBs is projected to increase manifold times in the near future. Concerns have been raised whether this demand will create issues related to element resources, market access and supply chains on the long-term. The global distribution of lithium and cobalt resources are highly unequal with Europe being in an inferior situation. Numerous (sometimes controversial) reports on the availability of “battery materials” were published recently. Although long-term predictions are naturally difficult, there is broad consensus that the development of alternative batteries based on abundant elements is an important strategy to minimize the risk of resource depletion or of restricted access. This has recently resurged a lot of interest in alternatives to LIBs. A major approach is to adopt the LIB rocking chair concept to other working ions, i.e. replacing Li+ by more abundant ions such as Na+, K+, Mg2+, Ca2+ or Al3+, while at the same time also avoiding other critical elements. An additional argument for multivalent ions is that their use is one of the very few options to theoretically surpass the charge/energy density of LIBs.
On the other hand, the electrochemistry of alternative ions can be an extreme challenge, especially considering multivalent ions. Unconventional approaches are therefore needed to overcome unfavourable ion size and/or polarization effects.
The SEED project is such an unconventional approach, breaking with what has been common sense in the design of electrode materials so far: Instead of intercalating ions into solid electrodes, the SEED project aims at intercalating solvated ions into solid electrodes.
Overall objectives are:
- Understand the intercalation of solvated ions into solid electrodes
- Starting from graphite, explore the concept for other materials
- Starting with abundant Na+, explore the concept for multivalent ions
- Combine experiment with theory.