Synthesis of novel organic-ligand-doped sodium bis(oxalate)-borate complexes with tailored thermal stability and enhanced ion conductivity for sodium ion batteries

A series of novel organic-ligand-doped sodium bis(oxalate)-borate complexes, including sodium bis [salicylato(2-)]-borate (NBSB), sodium[salicylato benzenediol]borate (NBDSB), sodium bis[oxalate]borate (NBOB) and its derivatives NBOB(C2H2O4)(0.2), NBOB(C7H4O3)(0.2), NBOB(C7H4O3)(0.6), NBOB(C6H6O2)(0.6) and NBOB(C6H6O2)(0.3) fabricated by solid-state reaction are firstly developed as new-type electrolytes for sodium ion batteries. These resulting sodium boron salts possess good solubility in an abroad range of organic solvents (such as PC, AN, DMF, PC + AN, PC + DMF), tailored thermal stability from 300 to 353 degrees C, improved ion conductivity (>1 x 10(-3) S cm(-1)), environmental friendliness and low cost. Therefore, we believe that these new-type sodium boron salts show great potential as a new class of electrolyte for high-performance sodium ion batteries. (C) 2013 Elsevier B.V. All rights reserved.