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[Image above] Credit: Pixabay

Recent global events have turned the spotlight on unequal treatment based on race, gender, national origin, and more, and has ignited passions for creating greater equity for all people.

We scientists and engineers are not immune from our own biases, whether explicit or implicit. But one of The American Ceramic Society’s core values is to build a welcoming and diverse community of peers.

In this light, the journals group is very proud of the WOMEN IN GLASS issue of the International Journal of Applied Glass Science. Organized and edited by IJAGS co-editor Alicia Durán, Lili Hu, and Kathleen Richardson, the issue contains 17 top-quality works led by women researchers. Topics include basic science, modeling, in-situ characterization, application, and design of glasses for energy, healthcare, and optical devices, among others.

A look at articles in WOMEN IN GLASS

For many years I have been interested in advanced energy, so I was intrigued by Qun Zu’s paper on the effects of high gamma irradiation on glass fibers.

In what applications are glass fibers subjected to massive doses of radiation (equivalent to 1 million times the amount that could kill humans)? As it turns out, glass-reinforced laminated epoxy composites are the material of choice for structural support in tokomaks and other nuclear fusion experimental devices. (Nuclear fusion, which occurs in our sun, is the joining of atomic nuclei through extreme velocity collisions or thermal events.)

The article is an in-depth study of how properties and structures of the fibers evolve while exposed to radiation, and it discusses substantial advances to the basic science in this field.

I was drawn to two observations. First, the fibers darkened substantially, but the compositions and mechanical properties remained largely constant, aside from changes to oxygen content. The authors explore the structural changes leading to the color change in great depth.

Second, the mechanical properties of the composites were substantially lower after irradiation. Because their data keeps with literature that indicates epoxy is degraded by irradiation, the authors suggest the glasses are adequate for nuclear fusion applications but encourage that different polymers be explored as well.

The paper, published in International Journal of Applied Glass Science, is “Glass resistance to radiation–part I: Preliminary investigation of three commercial glass fibers” (DOI: 10.1111/ijag.15612).

Photographs of various glass samples illustrating glass color change after exposure to 5M Gy radiation. Top: before radiation. Bottom: after radiation. Credit: Zu et al., International Journal of Applied Glass Science

Another article in the issue reviews state-of-the-art research on glass anodes for lithium-ion batteries, a topic to which we can all relate.

Batteries are everywhere, from cell phones and cars to airplanes and grid electrical power. Lithium-ion batteries have a high energy density, i.e., electricity storage capacity for a given volume. Unlike lead-acid batteries used in cars, which have liquid electrolytes, lithium-ion batteries use solid or semi-solid electrolytes. And unlike other dry-cell technologies, such as nickel metal hydride or nickel cadmium, lithium-ion batteries have the potential for hundreds of charge-discharge cycles with steady performance while also being environmentally friendly.

While lithium-ion batteries are commonly used in rechargeable items today, they have not yet lived up to their full potential. Current anode materials contain much less lithium than is theoretically possible—and hence the energy capacity is not yet optimized. An important factor for this limitation is safety. Quite a few incidences of lithium batteries overheating and catching fire have been in the news the past few years—from “hoverboards” to Boeing 787 airplanes. Engineered glass has the potential to improve storage capacity with improved safety.

The key design parameter for glass anodes is flexibility in the structure to accommodate the lithium ions during charging and discharging. The recent CTT post on envisioning battery electrodes is helpful, but it does not tell the full story.

As lithium flows into the anode, the structure must expand (more on that later). As it flows out, the structure must either stay stable or collapse down in a controlled fashion. If the structure is too rigid, the flows of lithium will lead to cracking or total collapse (pulverization) of the anode. But glass is brittle, right? Well, because glass has a somewhat open framework compared to crystalline ceramics, glass with the right compositions can reorganize to accommodate the lithium.

Schematic 2D representation of tetrahedrally coordinated Li2O–SiO2 glass. This glass is one being considered for use as an electrolyte due to its open structure. Credit: Ren et al., Journal of the American Ceramic Society

In her article, Yanfei Zhang reviews the structure and performance of four glass systems: tin-based, silica-carbon hybrids, tellurium-vanadium glass, and germanium glass. Each has specific benefits and challenges.

I thought the tellurium-vanadium glass was interesting because compositions are specifically designed to accommodate the lithium through engineered order-disorder transitions. And the germanium-based glass uses a designed mesoporous structure that helps bonding to the electrolyte, shortens diffusion length for the lithium ions, and accommodates the volume changes during the charge-discharge cycle.

These developments show promise for improving battery performance, and the author provides information about future work that is needed to continue moving forward.

The paper, published in International Journal of Applied Glass Science, is “Glass anodes for lithium ion batteries: Insight from the structural evolution during discharging/charging” (DOI: 10.1111/ijag.15079).

These papers are but two of the great articles for the WOMEN IN GLASS issue of IJAGS. Please be sure to read them all. They are free-to-read through June and July.