In Operando Small-Angle Neutron Scattering Study of\nSingle-Ion Copolymer Electrolyte for Li-Metal Batteries

Abstract

To enable a renewable energy future,\nelectrochemical energy storage\nremains as one of the main challenges of today’s society. Lithium-ion\nbatteries have been shown to be of great potential in that respect,\nbut they still suffer from safety instabilities arising from the use\nof flammable liquid electrolytes. Solid electrolytes are an interesting\nalternative that provide the required safety properties. We introduce\na highly stable solid single-ion diblock copolymer electrolyte poly­(deuterated\nstyrene)-<i>block</i>-poly­(poly­(ethylene glycol) methyl\nether styrene-<i>co</i>-lithium styrene sulfonyl­(trifluoromethane\nsulfonyl)­imide), denoted PS­(d)-<i>b</i>-P­(SPEG-<i>co</i>-STFSILi). Lithium metal batteries based on PS­(d)-<i>b</i>-P­(SPEG-<i>co</i>-STFSILi) are probed in operando with\nsmall-angle neutron scattering in order to investigate their suitability\nas safe batteries using lithium metal anodes. We compare cell operation\nwhen cycling at 0.5 C at 80 °C to 0.7 C at 90 °C, which\nrepresent severe working conditions for the battery. More than 200\ncycles are performed, showing the inflation of the ionic pathways\nthrough cycling at 0.7 C, whereas at 0.5 C and 80 °C, battery\nperformance and morphology remain unchanged.