Could Batteries Last Longer? — Chromatography Explores

Batteries are a key piece of technology in the modern world and their impact is only likely to increase. From electric cars to storing solar power batteries are big business — but we know surprisingly little about what actually goes on inside them.

A recent study published in the journal Rapid Communications in Mass Spectrometry — Identification and formation mechanism of individual degradation products in lithium-ion batteries studied by liquid chromatography/electrospray ionization mass spectrometry and atmospheric solid analysis probe mass spectrometry — has used chromatography to increase our knowledge of battery reactions and products.

Li-ion batteries power the world

Lithium ion batteries (Li-ion) are found everywhere — laptops, mobile phones and even electric cars all use Li-ion battery technology to power them. They are popular because they have an excellent power-to-weight ratio — with their weight being much lighter than other commonly available rechargeable batteries. Whilst Li-ion technology means a battery can store 150 watt-hours of electrical energy per kilogram, the value for a metal-hydride battery is less than 100 watt-hours and for lead-acid the figure is a measly 25 watt-hours per kilogram.

The technology in a Li-ion battery pack is complex, with temperature sensors, voltage and current regulators and controllers, a voltage tap that monitors individual cells in the pack and a charge monitor to make sure the battery is charged ok.

But one area where researchers have been looking at in detail is the chemistry of the batteries. To improve the batteries and help our smartphones last that little bit longer to allow us to catch Magneton* and Slowpoke* — we need to know what is going on chemically as our batteries charge and discharge.

Still an anode and cathode inside

Although a Li-ion battery is a complex piece of kit — it still works on the same foundations you learnt at school. There are two electrodes — a cathode (positive) and an anode (negative) along with an electrolyte (the medium through which the ions or electric charge flows). In a LI-ion battery, the cathode is typically made of a lithium compound and the anode of carbon or graphite.

But although we know how the charges flow when we are charging or discharging a battery — the compounds that are formed inside the battery are a mystery. In the paper above, the team used liquid chromatography with mass spectrometry to identify the compounds formed during the use of a battery — the compounds that could affect the efficiency of the battery. The preparation of complex samples for mass spectrometry is discussed in the article, Recent Advances in the Applications of Mass Spectrometry to Environmental Matrix Analysis.

The team were able to identify some of the degradation products at the cathode and a product at the anode. They have also suggested some reaction mechanisms for the products found. With further work, the team hope to identify further products — which could help to improve battery technology and lifetime. Good news for Pokemon hunters everywhere.

*Pokemon-Go characters (so I’m told…)