Solid polymer electrolytes (SPEs), such as polyethylene oxide (PEO)–LiTFSI, polycarbonates, and block-copolymer systems, trade some conductivity (10⁻⁵–10⁻³ S cm⁻¹ at 60–90 °C) for exceptional processability. Moreover, SPEs can be cast as free-standing films, laminated at low pressure to electrodes, and formulated with ceramic fillers or ionic plasticizers to tune modulus and transport.
An Introduction to Solid Polymer Electrolytes
A good SPE must possess these following properties:
- a good dissolution of Li salts
- a high Li transference number (T+)
- a low glass transition temperature (Tg)
- electrochemical stability towards most common electrode materials
- a low degree of crystallinity
- mechanical stability
- low temperature sensitivity
- ability to produce pin-hole-free membranes
Cathode Electrolyte Interphase (CEI)
In solid polymer electrolytes, the CEI may contain alkyl-lithium species and decomposition products of the polymer matrix itself.
Nuvvon
- 1Ah NMC811/Graphite and NMC9/Li-metal – a real hint at what solid state lithium metal cells can deliver with a Solid Polymer Electrolyte.
- Solid State Passes Nail Test – a comparison of a conventional liquid electrolyte to the Nuvvon solid state design.
See also
Electrolyte Decomposition, Ionic Liquid Electrolytes, Solid State Battery