Naval Research Laboratory (NRL) Materials Science and Technology Division’s researchers have developed innovative solid-state batteries by utilizing ionic liquids instead of highly acidic electrolytes. These ionic liquids are utilized to produce a polymer electrolyte containing polyvinyl alcohol and ionic liquid.
The new kind of solid-state batteries have up to 1.8 V of discharge voltages. Ionic liquids are ambient temperature molten salts exhibiting unique attributes. For instance, they do not react in industrial and electrochemical applications, non- flammable and virtually has no vapor pressure. When reactive ionic liquids are used in solid-state cells, they can substitute highly alkaline electrolytes, including zinc and manganese oxide, utilized in conventional batteries.
The researchers conducted a detailed investigation to evaluate the corrosion resistance of various metals in ionic liquids. They performed a series of tests to study the reactions of various metal oxides with ionic liquids such as hydrogen sulphate. Based on these experiments, they found that ionic liquids could function as an electrolyte in both liquid and solid state batteries as well as a reactive specimen in the battery’s electrochemical structure.
The scientists designed the solid-state batteries utilizing regular anode and cathode materials such as silver oxide, lead dioxide and magnesium dioxide, and 1-ethyl-3-methylimidazolium hydrogen sulphate as ionic liquid. However, dihydrogen phosphate and nitrate anion-based ionic liquids can perform well in this kind of a battery design.
The ionic liquids can be utilized to develop new kind of rechargeable battery systems by substituting electrolytes in normal lead-acid batteries or nickel-metal hydride batteries. Research work is in progress to design such kind of rechargeable ionic liquid power source.