Monthly Archives: July 2015

A Small Gift to Dr. Loh Makes a Big Hit

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Presenting NanoCenter plaque to UMD President Loh.

Maryland NanoCenter staff thank UMD president Loh for recent visit, commemorated with high-tech plaque.

UMD president Dr. Wallace Loh (center) receives a plaque containing gold coated silicon wafers, key components of semiconductor and micro-machine fabrication. The wafers, created by the Maryland NanoCenter staff, commemorates Loh’stour of the NanoCenter’s FabLab, a high-tech on-campus facility for processing nano-scale materials and components. Logos of the other Big Ten Schools, of which University of Maryland is the newest school, surround the central disk. Dr. Gary Rubloff, the NanoCenter’s Director (right),Fab Lab staffer Thomas Loughran (below left) and Dr. Jim O’Connor look on.

Closeup of President Loh plaque.

A plaque to commemorate UMD president Loh on a recent visit to the NanoCenter. Silicon wafers are etched with each of the Big Ten school’s logos.

A set of gold and silicon wafers, used in high-tech fabrication of semiconductors and micro and nano machines, is etched to commemorate the July 1 visit of UMD president Dr. Wallace Loh to the Maryland NanoCentre’s FAB Lab, a state-of-the-art facility where such materials are commonly used. The large upper disk commemorates the University of Maryland’s entrance into the Big Ten athletic conference. The logo of the University of Michigan — where Loh earned a PhD in psychology– lies to the left of that of Maryland’s “Terp” logo.

Activation of a MnO2 cathode by water-stimulated Mg2+ insertion for a magnesium ion battery

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Jaehee Song, Malakhi Noked, Eleanor Gillette, Jonathon Duay, Gary Rubloff, and Sang Bok Lee
Physical Chemistry Chemical Physics
Issue 7, 2015, 5256-5264
DOI: 10.1039/C4CP05591H
First published online Jan 15, 2015

Magnesium batteries have been considered to be one of the promising beyond lithium ion technologies due to magnesium’s abundance, safety, and high volumetric capacity. However, very few materials show reversible performance as a cathode in magnesium ion systems. We present herein the best reported cycling performances of MnO2 as a magnesium battery cathode material. We show that the previously reported poor Mg2+ insertion/deinsertion capacities in MnO2 can be greatly improved by synthesizing self-standing nanowires and introducing a small amount of water molecules into the electrolyte. Electrochemical and elemental analysis results revealed that the magnitude of Mg2+ insertion into MnO2 highly depends on the ratio between water molecules and Mg2+ ions present in the electrolyte and the highest Mg2+ insertion capacity was observed at a ratio of 6H2O/Mg2+ in the electrolyte. We demonstrate for the first time, that MnO2 nanowire electrode can be “activated” for Mg2+ insertion/deinsertion by cycling in water containing electrolyte resulting in enhanced reversible Mg2+ insertion/deinsertion even with the absence of water molecules. The MnO2 nanowire electrode cycled in dry Mg electrolyte after activation in water-containing electrolyte showed an initial capacity of 120 mA h g−1 at a rate of 0.4 C and maintained 72% of its initial capacity after 100 cycles.