Alkyl-spiroborate salts and their use in electrochemical cells

Novel alkylspiroborate salts are claimed. A borate salt is of formula (I). Independent claims are included for; (1) An electrolyte containing the salt (I) and (2) An electrochemical cell containing the electrolyte. M = metal ion, tetra-alkylammonium ion, PRaRbRcRd, p(NRaRb)kRcmRd(4-k-m), C(NRaRb)(NRcRd)(NReRf), C(R)3, tropylium or heterocyclenes containing P, N, S or O or corresponding condensed heterocyclic systems; k = 1-4; m = 0-3; k+m ≤ 4; Ra-Rf=H, 1-8C alkyl or aryl, optionally substituted by F, Cl or Br; R=optionally substituted aromatic; x,y=1-6; R-R=1-8C alkoxy or carboxyl, optionally directly bonded to each other by a single or double bond.