Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a new solid-state lithium metal battery that can be charged and discharged at least 6,000 times -- a possible breakthrough that offers new understanding into the materials used for these batteries.
Lithium batteries are critical for growth of the electric vehicle industry, as most EVs use lithium-ion batteries. Securing enough lithium supply for battery production has been a big focus for governments and EV industry stakeholders as the demand for materials continues to grow.
The researchers, who published their findings in Nature Materials, described a new way to make solid-state batteries with a lithium metal anode. Researchers noted that one of the biggest challenges of lithium batteries is the formation of dendrites on the surface of the anode, which can grow and cause the battery to short or catch fire. The research team aimed to design a solution to deal with dendrites.
“Lithium metal anode batteries are considered the holy grail of batteries because they have 10 times the capacity of commercial graphite anodes and could drastically increase the driving distance of electric vehicles,” said Xin Li, associate professor of materials science at SEAS and senior author of the paper. “Our research is an important step toward more practical solid-state batteries for industrial and commercial applications.”
Li and the research team designed a multilayer battery that added materials of varying stabilities that prevented the penetration of lithium dendrites.
“In this design, when lithium ions move from the cathode to the anode during charging, the lithiation reaction is constricted at the shallow surface and the ions attach to the surface of the silicon particle but don’t penetrate further,” the research said. “This is markedly different from the chemistry of liquid lithium-ion batteries in which the lithium ions penetrate through deep lithiation reaction and ultimately destroy silicon particles in the anode.”
The design creates a homogenous surface that can be recharged in only about 10 minutes. The researchers used a postage stamp-sized pouch cell version of the battery -- 10 to 20 times larger than the coin cell made in most university labs. After 6,000 cycles, the battery retained 80% of its capacity.
