Aluminum Could Boost Rechargeable Batteries
Engineering360 News Desk | August 18, 2015A team of researchers at Massachusetts Institute of Technology (MIT) and Tsinghua University in China has found a way to improve how electrodes in rechargeable batteries expand and shrink during each cycle.
The gray sphere at center represents an aluminum nanoparticle, forming the "yolk." The outer light-blue layer represents a solid shell of titanium dioxide, and the space in between the yolk and shell allows the yolk to expand and contract without damaging the shell. Source: MIT, Image credit: Christine Daniloff They have developed an electrode made of nanoparticles with a solid shell, and a “yolk” inside that can change size repeatedly without affecting the shell. The researchers say this could improve cycle life and boost the battery’s capacity and power.
The use of nanoparticles with an aluminum yolk and a titanium dioxide shell has proven to be “the high-rate champion among high-capacity anodes,” the team says.
“We made a titanium oxide shell that separates the aluminum from the liquid electrolyte between the battery’s two electrodes,” says MIT professor Ju Li. The shell does not expand or shrink much, he says, so the solid-electrolyte interphase (SEI) coating on the shell is stable and does not fall off, and the aluminum inside is protected from direct contact with the electrolyte.
The researchers used aluminum because it is a low-cost option and had a theoretical capacity of 2 Ah/g.
“These yolk-shell particles show very impressive performance in lab-scale testing,” says David Lou, an associate professor of chemical and biomolecular engineering at Nanyang Technological University in Singapore, who was not involved in this work. “To me, the most attractive point of this work is that, the process appears simple and scalable.”
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