No more exploding batteries? Researchers develop water-based Lithium batteries to reduce chance of fire
Scientists in the United States believe they have developed a solution to the problem of exploding high energy Lithium batteries.
Researchers at University of Maryland and the US Army Research Laboratory (ARL) have developed a safe lithium-ion battery which uses a water-salt solution as its electrolyte.
The development comes after Samsung for example was forced to withdraw its entire range of Galaxy Note 7 phablets because of a fire risk.
This is because the Lithium batteries used in smartphones and laptops are typically non-aqueous, as they can reach the higher energy levels needed by those devices.
But the US researchers published their findings in the journal Joule, which revealed they have now come with a way to develop an aqueous (i.e. water-based) Lithium battery that can deliver high energy.
These aqueous lithium-ion batteries should be much safer as the water-based electrolytes cannot catch fire, compared to the flammable organic solvents used in non-aqueous batteries.
The researchers explained their aqueous Lithium battery uses salt water, and “reaches the 4.0 volt mark desired for household electronics, such as laptop computers, without the fire and explosive risks associated with some commercially available non-aqueous lithium-ion batteries.”
“In the past, if you wanted high energy, you would choose a non-aqueous lithium-ion battery, but you would have to compromise on safety,” said co-senior author Dr. Kang Xu, ARL fellow. “If you preferred safety, you could use an aqueous battery such as nickel/metal hydride, but you would have to settle for lower energy. Now, we are showing that you can simultaneously have access to both high energy and high safety.”
The research comes after a 2015 study that produced a similar 3.0 volt battery with an aqueous electrolyte.
However that advance was prevented from achieving higher voltages by the so-called “cathodic challenge,” in which one end of the battery, made from either graphite or lithium metal, is degraded by the aqueous electrolyte.
To solve that problem, and make a battery capable of producing four volts, University of Maryland assistant research scientist Chongyin Yang, designed a new gel polymer electrolyte coating that could be applied to the graphite or lithium anode. That coating expels water molecules from the vicinity of the electrode surface.
“The key innovation here is making the right gel that can block water contact with the anode so that the water doesn’t decompose and can also form the right interphase to support high battery performance,” said co-senior author Chunsheng Wang, Professor of Chemical & Biomolecular Engineering at the University of Maryland’s A. James Clark School of Engineering.
“The addition of the gel coating also boosts the safety advantages of the new battery when compared to standard non-aqueous lithium-ion batteries and boosts the energy density when compared to any other proposed aqueous lithium-ion batteries,” Wang added.
But the researchers warned that development still needs to be carried out before the new battery is perfected and can be commercialised.
A number of airlines around the world have also banned the bulk shipment of lithium-ion batteries on their aeroplanes over fire safety concerns.
Those decisions arose after growing concerns of the fire risks posed by lithium-ion batteries. The Federal Aviation Administration has previously carried out tests, two of which revealed that batteries could cause a major fire on board an aircraft.