Researchers at the US Missouri University of Science and Technology have used a thin-film coating technique to make lithium-ion batteries more reliable and longer lasting.
The scientists used atomic layer deposition (ALD) to dope and coat lithium magnesium nickel oxygen (LMNO) with iron oxide at the same time.
Using the technique allowed the scientists to make rechargeable lithium-ion batteries that retained 93% capacity after 1,000 cycles at room temperature, and 91% at elevated temperatures.
The researchers reported that around 0.6-nanometer coatings produced the best results. The coating process was carried out at 450 degrees Celsius under reduced pressure.
Dr. Xinhua Liang, assistant professor of chemical and biochemical engineering at Missouri S&T, lead the study which was published in Scientific Reports, a Nature publishing group journal.
The operating voltage window of LMNO has always made it a potential candidate for use in hybrid electric vehicles (HEVs).
However, its high-capacity fade during cycling at high temperatures and manganese (3+) dissolution by hydrogen fluorine meant its commercial use was limited.
“Unlike current research practice that either covers the particles’ surface with insulating film or dopes the particles to improve the performance of the battery, this ALD process combines the coating and doping processes into one,” Liang said.
“This is the first report for a unique phenomenon of ionic iron entering the lattice structure of LMNO during the ALD coating process,” added Rajankumar Patel, a Missouri S&T PhD graduate who did the majority of the experimental work in the project.
The research team included Dr Amitava Choudhury, assistant professor of chemistry at Missouri S&T, and Dr Ying-Bing Jiang, senior research scientist in the TEM Laboratory at the University of New Mexico.
Their paper is titled ‘Employing Synergetic Effect of Doping and Thin-Film Coating to Boost the Performance of Lithium-Ion Battery Cathode Particles’.