Quantifying Stress in Graphene Supercapacitor Electrodes

Researchers from Texas A&M University have shown that a supercapacitor responds to charging by stretching and expanding, storing energy. This discovery can be applied to the construction of novel materials for flexible electronics or other devices that need to be robust and have an efficient energy storage capacity.

Electrochemomechanical Coupling of 2D Nanomaterial Supercapacitor Electrodes
Graphical abstract. Image Credit: Matter (2023). DOI: 10.1016/j.matt.2023.08.017

Dr. Jodie Lutkenhaus, Associate Department head of Internal Engagement and Chemical Engineering Professor, worked with Dr. Dimitris Lagoudas, Professor of Aerospace Engineering, and Dr. James Boyd, Assistant Professor of Aerospace Engineering, on a new study published in Matter.

We measured stresses that developed in graphene-based supercapacitor electrodes and correlated the stresses to how ions move in and out of the material. For example, when a capacitor is cycled, each electrode stores and releases ions that can cause it to swell and contract.

Dr. Jodie Lutkenhaus. Associate Professor, Department Head, Internal Engagement and Chemical Engineering, Texas A&M University

According to Lutkenhaus, this recurrent motion might result in the accumulation of mechanical stresses, which can lead to device failure. Her research aims to develop a device that detects mechanical stresses and strains in energy storage materials as they charge and discharge.

The device provides insights into measuring the mechanical behavior of an electrode while charging and discharging, which can be difficult to detect in real-time.

We are pioneering experimental methods to measure the simultaneous electrochemical and mechanical response of electrodes. Our research is now moving from supercapacitors to batteries.

Dr. James Boyd, Assistant Professor, Aerospace Engineering, Texas A&M University

Mechanical damage reduces battery cycle life; hence, new hardware and models are required to interpret experimental observations to disentangle the impacts of mass diffusion, reactions, inelastic deformation, and mechanical damage.

Internal and external mechanical forces can cause batteries and capacitors to fail. Internal stresses arise when batteries undergo repetitive cycling of the device, while external stresses might originate from impact or penetration of the device.

When these stresses occur, the battery needs to be able to survive the damage. According to Lutkenhaus, it is critical to understand how mechanical stress occurs in the device’s electrochemical state.

Lutkenhaus added, “We developed an instrument that can do just that. By gaining this critical insight, we might be able to design safer energy storage devices that will last longer.

The study’s goal is to create energy storage devices that can withstand structural loads and eventually replace carbon-fiber reinforced plastics used as structural panels in aircraft, boosting energy efficiency.

This article is the outcome of an ongoing collaboration between chemical engineering and aerospace engineering scientists. This research provides a unique understanding of how nanomaterials can be used for lightweight and strong energy storage devices for aerospace applications.

Dr. Dimitris Lagoudas, Professor, Aerospace Engineering, Texas A&M University

Journal Reference:

Loufakis, D., et al. (2023) In situ electrochemo-mechanical coupling of 2D nanomaterial supercapacitor electrodes. Matter. doi:10.1016/j.matt.2023.08.017