The new batteries use a water-salt solution as their electrolyte. This removes the risks carried by current commercial models which contain a non-water based chemical composition. In trials the batteries were subjected to high heating and puncture, and they did not ignite. The solid-electrolyte-interphase is stabilized by graphite and lithium-metal anodes in aqueous electrolyte.
Discussing the technology further, the lead researcher Dr. Kang Xu, who works at the U.S. Army Research Laboratory (ARL), told the BBC: “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. If you preferred safety, you could use an aqueous battery such as nickel/metal hydride, but you would have to settle for lower energy.” The new invention succeeds in providing high energy and safety.
Current lithium-ion batteries carry the intrinsic disadvantages of being flammable, toxic, and highly sensitive to ambient atmosphere. This has been overcome with the new battery. Initial work led to the creation of a 3 volt battery; going beyond this appeared difficult due to electrode degradation. The latest development has led to a 4 volt version. This was achieved by coating the anode with the protective gel polymer. This allows the battery to be used with laptop computers. This means the battery, as it is commercialized, will be suitable for business travelers, offering sufficient power as well as a low safety risk.
The new research is published in the journal Joule. The article is titled “4.0 V Aqueous Li-Ion Batteries.”
In related battery news, engineers and microbiologists have invented a new type of battery based on a microbial fuel cells. The battery can be activated by spit and it is intended to be used in extreme conditions. See “New battery is activated by spit.”
