An ion transporting solvent maintains very low vapor pressure, contains
flame retarding elements, and is nontoxic. The solvent in combination
with common battery electrolyte salts can be used to replace the current
carbonate electrolyte solution, creating a safer battery. It can also be
used in combination with polymer gels or solid polymer electrolytes to
produce polymer batteries with enhanced conductivity characteristics. The
solvents may comprise a class of cyclic and acyclic low molecular weight
phosphazenes compounds, comprising repeating phosphorus and nitrogen
units forming a core backbone and ion-carrying pendent groups bound to
the phosphorus. In preferred embodiments, the cyclic phosphazene
comprises at least 3 phosphorus and nitrogen units, and the pendent
groups are polyethers, polythioethers, polyether/polythioethers or any
combination thereof, and/or other groups preferably comprising other
atoms from Group 6B of the periodic table of elements.