Working with a grant from Ford Motor company, researchers Randall Goldsmith and colleagues at the University of Wisconsin-Madison developed fluorescent compound that can attach to lithium ions to show if batteries are leaking.
The researchers worked with 2-(2-hydroxyphenyl)naphthoxazole, or HPNO, a molecule that fluoresces when it attaches to lithium ions. They added a "visible pump" to help prevent photobleaching and other damage to provide real-time tracking of lithium ions via widefield fluorescence microscopy. The fluorophore can be excited with visible light and can be used on a plasticized polymer electrolyte lithium battery.
The next step is to test the molecule in a realistic version of a battery cell.