It’s probably safe to say that just about everyone is impressed with the incredible performance offered by lithium-ion batteries. They make our cell phones and laptops viable for real-world use and will be powering just about every electric vehicle on the road. These batteries do have one problem however: they sometimes catch fire. That’s not good. Fortunately, scientists at Cambridge University think they’re on the road to solving this problem - a new technique allows them to “see” the chemistry at work inside batteries.
The reason lithium-ion batteries do catch fire involves tiny lithium particles that form fibers known as dendrites. Over several charge/discharge cycles, these dendrites can accumulate on the battery’s carbon anodes. Once that happens, short circuits can occur, resulting in rapid overheating and combustion. Scientists have previously been able to study the principles of dendrite formation using theoretical models and microscopes, but had not been able to quantify the amount of dendrites formed... until now.
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Using Nuclear Magnetic Resonance (NMR) spectroscopy, the Cambridge scientists were able to watch the chemical reactions actually taking place within a 1-cm long battery enclosed in an aluminum bag. While they have yet to figure out a way of dealing with the dendrites, it’s definitely a step in the right direction.
"Fire safety is a major problem that must be solved before we can get to the next generation of lithium-ion batteries and before we can safely use these batteries in a wider range of transportation applications. Now that we can monitor dendrite formation inside intact batteries, we can identify when they are formed and under what conditions,” wrote Professor Clare Grey of the Department of Chemistry. “Our new method should allow researchers to identify which conditions lead to dendrite formation and to rapidly screen potential fixes to prevent the problem."
The research was recently published in the journal Nature Materials.