USA: Lithium (Li-ion) batteries used to power plug-in hybrid and electric vehicles show overall promise to "fuel" these vehicles and reduce greenhouse gas emissions, but there are areas for improvement to reduce possible environmental and public health impacts, according to a "cradle to grave" study of advanced Li-ion batteries recently completed by Abt Associates for the US Environmental Protection Agency (EPA).
"While Li-ion batteries for electric vehicles are definitely a step in the right direction from traditional gasoline-fueled vehicles and nickel metal-hydride automotive batteries, some of the materials and methods used to manufacture them could be improved," said Jay Smith, an Abt senior analyst and co-lead of the life-cycle assessment.
Smith said, for example, the study showed that the batteries that use cathodes with nickel and cobalt, as well as solvent-based electrode processing, show the highest potential for certain environmental and human health impacts. The environmental impacts, Smith explained, include resource depletion, global warming, and ecological toxicity—primarily resulting from the production, processing and use of cobalt and nickel metal compounds, which can cause adverse respiratory, pulmonary and neurological effects in those exposed.
There are viable ways to reduce these impacts, he said, including cathode material substitution, solvent-less electrode processing and recycling of metals from the batteries.
The study, carried out through a partnership with EPA, the US Department of Energy, the Li-ion battery industry, and academicians, was the first life-cycle assessment to bring together and use data directly provided by Li-ion battery suppliers, manufacturers, and recyclers. Its purpose was to identify the materials or processes within a Li-ion battery's life cycle that most contribute to impacts on public health and the environment, so that battery manufacturers could use this information to improve the environmental profile of their products, while the technology is still emerging.
It also sought to evaluate the potential impacts of a nanotechnology innovation (i.e., a carbon nanotube anode) that could improve battery performance.