RESEARCH & INNOVATION
RECYCLE , RECHARGE , REUSE
New recycling method could offset battery waste of the future .
BY LIEZEL LABIOS , MS ’ 10 , PHD ’ 12
ELECTRIC VEHICLES may someday make gas-guzzling emissions a thing of the past , but they will eventually leave behind a different by-product to reckon with : millions of tons of spent lithiumion batteries .
Without efficient or economical battery recycling systems in place , less than 5 percent of the lithium-ion batteries around the world are currently recycled . As these batteries get tossed , so do valuable metals like cobalt , an essential component that also comes with serious environmental and ethical costs . Half of the world ’ s cobalt is mined in the Democratic Republic of Congo , for instance , where hazardous conditions and child labor have been reported .
This makes efficient battery recycling a critical issue , one that UC San Diego researchers are determined to tackle with methods that could give these batteries new life and keep them out of landfills .
Nanoengineers at the Jacobs School of Engineering ’ s Sustainable Power and Energy Center have devised a novel way to recycle lithium-ion batteries piece by piece — starting with the cathode , or the positive side of the battery , in which the most cobalt is used . The process can restore cathodes to near-mint condition and is viable for not just electric vehicle batteries but also those used in laptops , smartphones , tablets and digital cameras .
The method was developed in the lab of nanoengineering professor Zheng Chen and uses a chemical bath and sound-wave technology to break the lithium-cobalt particles off degraded cathodes . Afterward , the particles are pressurized in a lithium salt bath and then dried , quickly heated to 800 ° C and cooled slowly .
Remarkably , the new cathodes made from these regenerated particles had the same energy storage capacity , charging time and lifetime as the originals . The recycling process is efficient as well . Restoring one kilogram of particles only uses 6 megajoules of energy — the equivalent of three-quarters of a cup of gasoline — and half the energy required by other recycling processes currently being developed . That ’ s because Chen ’ s process preserves something valuable that other methods destroy — the cathode microstructure . “ These cathodes have
PROMISING POWER Materials in modern batteries have proven difficult to recycle , but nanoengineer Zheng Chen ( left ) and postdoc Yang Shi have developed an efficient method .
“ The sooner we solve this problem , the less it will be a problem for future generations .”
— ZHENG CHEN , NANOENGINEERING PROFESSOR
specific , well-designed microscopic structures that determine battery performance . A lot of engineering and energy are already spent making these structures . We don ’ t want all that to go to waste ,” says Chen .
Moving forward , researchers are optimizing this process so that it can be economical on an industrial scale . And on the flipside , Chen ’ s team is now working on a process to recycle the anode , or the battery ’ s negative electrode . “ We ’ re doing our part now to ensure that one day , lithium-ion batteries will be just as easy and economical to recycle as lead-acid batteries ,” says Chen . “ The sooner we solve this problem , the less it will become a problem for future generations .”
14 TRITON | FALL 2018