As a chemist, I am appalled by mainstream media reports that investigators remain unsure about the causes for lithium-ion batteries catching fire onboard Boeing jets. Lithium-ion battery safety—or the lack thereof—is a matter of fundamental chemistry that must be addressed by Boeing and the Federal Aviation Administration (FAA). Known, reliable tests such as accelerated rate calorimetry (ARC) can determine whether the batteries will produce a chaotic runaway reaction.
As one of the strongest known reducing agents, lithium might very well cause an autocatalytic reaction with the carbonyl solvent chosen for the new batteries (J. Electrochem. Soc. 1999, DOI: 10.1149/1.1391893). Readily available ARC testing can determine the onset temperature and increase in pressure of any such reaction and provide the chemical understanding needed for certifying the safety of airline passengers. It is critical that the new Boeing batteries be tested using this premier standard.
Monitoring the batteries’ behavior in flight, as has been proposed, will do nothing to stop a potential burnout if the reaction cannot be prevented in the first place. Modifying the environment of the batteries with insulation could possibly exacerbate overheating to a critical temperature. Before commercial flights with these lithium-ion batteries onboard resume, Boeing, FAA, and the scientific community must ensure that all scientific protocols have been thoroughly investigated and made public.
A. Bryan Lees