Communications of the ACM
Precision Nanobatteries by the Billions
Complete nanobatteries are formed in each nanopore of a dense nanopore array (2 billion per square centimeter) using atomic layer deposition.
Credit: Gary Rubloff / University of Maryland
Nanostructured batteries, when properly designed and built, offer promise for delivering their energy at much higher power and longer life than conventional technology.
To retain high energy density, nanostructures (such as nanowires) must be arranged as dense "nanostructure forests," producing three-dimensional nanogeometries in which ions and electrons can rapidly move. Researchers have built arrays of nanobatteries inside billions of ordered, identical nanopores in an alumina template to determine how well ions and electrons can do their job in such ultrasmall environments. The nanobatteries were fabricated by atomic layer deposition to make oxide nanotubes for ion storage inside metal nanotubes for electron transport, all inside each end of the nanopores.
The research is described in two papers published in Nature Nanotechnology, "An All-in-One Nanopore Battery Array," by Chanyuan Liu, Eleanor I. Gillette, Xinyi Chen, Alexander J. Pearse, Alexander C. Kozen, Marshall A. Schroeder, Keith E. Gregorczyk, Sang Bok Lee and Gary W. Rubloff, and "Batteries: Knowing when Small is Better," by Paul V. Braun and Ralph G. Nuzzo.
The tiny nanobatteries work extremely well: they can transfer half their energy in just a 30 second charge or discharge time, and they lose only a few percent of their energy storage capacity after 1,000 cycles. Researchers attribute this performance to rational design and well-controlled fabrication of nanotubular electrodes to accommodate ion motion in and out and close contact between the thin nested tubes to ensure fast transport for both ions and electrons.
The researchers say pPrecise structures can be constructed to assess the fundamentals of ion and electron transport in nanostructures for energy storage and to test the limits of three-dimensional nanobattery technologies.
This work was performed at the University of Maryland and was supported by the Nanostructures for Electrical Energy Storage Center, an Energy Frontier Research Center funded by the DOE Office of Science, Office of Basic Energy Sciences.
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