A New Class of Electrochemically and Thermally Stable Lithium Salts for Lithium Battery Electrolytes. V. Synthesis and Properties of Lithium Bis[2,3-pyridinediolato(2−)-O,Oʹ]borate

Synthesis, analysis, and purification of lithium bis[2,3-pyridinediolato(2−)‐ O , O ']borate (LBPB), is described. LBPB is the first lithium spiroborate known with a heterocycle, where the nitrogen works as an electron withdrawing atom. The anodic oxidation limit of this salt as determined from cyclic voltammetric measurements is 3.95 V vs. and it is increased by about 0.35 V when compared with lithium bis[1,2-benzenediolato(2−)‐ O , O ']borate. The gas phase energy of the highest occupied molecular orbital of the anion as obtained by the use of a semiempirical quantum mechanical method is −5.1 eV. No corrosion of aluminum is observed with this salt, which shows good protecting properties for the lithium electrode; therefore, this electrolyte may be suitable as an additive. © 2000 The Electrochemical Society. All rights reserved.