Battery electrolytes contain two mobile charged species of opposite charge and thus the traditional Ohm’s law, which applies to one mobile charged species, must be modified. This review uses a modified Ohm’s law to rank order electrolytes.
Significance and Impact
In the limit of low applied potentials, the current passed through an electrolyte is determined by two parameters: conductivity (κ) and a parameter that we call the current ratio. The highly-ranked electrolytes are characterized by low current ratio. Improving this parameter without sacrificing conductivity is a challenging but worthwhile goal.
- Published conductivity and current ratio values were aggregated for a variety of electrolytes: homopolymer electrolytes (HPE), gel polymer or cross-linked electrolytes (GPE), multicomponent polymer electrolytes (MCPE), and polymer electrolytes containing a sodium salt (NaPE). All electrolytes, excluding NaPE, contained a lithium salt.
- Electrolytes developed thus far are limited by a trade-off between conductivity and current ratio leading to an upper bound that is similar to the permeability-selectivity upper bound that has been found in gas permeation membranes.