Solvent-free lithium and sodium containing electrolytes based on pseudo-delocalized anionsElectronic supplementary information (ESI) available: Experimental procedure, synthesis of the MMnm11 salts, NMR spectra and additional figures and tables. See DOI: 10.1039/c8cc07076h

Mixing the standard battery salt LiTFSI with various Li-salts of novel pseudo-delocalized organic anions [N(CH 3 ) 2 ((CH 2 ) n SO 3 )((CH 2 ) m SO 3 )] − (MM nm 11 ), results in super-cooled solvent-free liquid electrolytes with glass transition temperatures of ca. 50 °C. Synthesis routes and full chemical characterisation of the new pseudo-delocalized anions are presented, as well as phase and thermal stabilities. The ion conductivities and electrochemical stabilities are evaluated towards lithium and sodium battery application. Synthesis and characterisation of super-cooled solvent-free liquid electrolytes for Li and Na batteries.