5 September 2017

New NMR technique could lead to better batteries

Li transport pathways as the content of ceramic particles in polymer-ceramic composite electrolytes increases. Li transport pathways as the content of ceramic particles in polymer-ceramic composite electrolytes increases.

Scientists can now observe lithium moving through an electrolyte in real time.

First, some background

Batteries have three essential parts: two electrodes (an anode and a cathode) and between them an electrolyte. Ions (charged particles) travel between the electrodes, generating electricity. Scientists are always trying to develop better batteries for energy storage out of materials like lithium.

Most lithium batteries today use liquid electrolytes, and that approach has its problems: Metallic bridges can form between the electrodes that short the battery. That's why scientists are trying to develop solid electrolytes that could be safer and yield more capacity.

What did scientists discover?

MagLab scientists have developed a new way, using nuclear magnetic resonance (NMR), to study the way lithium ions travel through solids. That journey is actually fairly complex, involving two variants, or isotopes, of lithium. As lithium-6 crosses the electrolyte, it swaps out for lithium-7. The MagLab experiments revealed that those pathways vary significantly, depending on the composition and structure of the solid electrolytes. Using a technique called operando NMR, the scientists could charge and discharge the batteries inside the instrument and observe changes in real time.

Why is this important?

The development of safe, high-energy-capacity batteries is of critical and growing importance. Replacing flammable liquid electrolytes with solid electrolytes in rechargeable Li-ion batteries will increase both performance and safety. This requires a fundamental understanding of lithium transport pathways. This study provides a novel and convenient tool for this type of research and contribute to better battery designs.

Who did the research?

Jin Zheng1, Mingxue Tang1, Po-Hsiu Chien1, Kevin Huang2, Hailong Chen3, Yan-Yan Hu1

1Florida State University; 2University of South Carolina; 3Georgia Institute of Technology

Why did they need the MagLab?

Lithium-6 NMR is a challenging measurement technique, due to the isotope's low natural abundance and low resonance frequency. High magnetic fields and fast sample spinning instrumentation available at the MagLab achieve the required sensitivity and resolution for this work. The MagLab's in-house development of an "in operando" NMR probe for battery studies has made it possible to probe lithium ion transport in real time.

THE TOOLS THEY USED

This research was conducted in the MagLab 500 MHz solid state NMR system at the MagLab's NMR Facility.

Details for scientists

Funding

This research was funded by the following grants: G.S. Boebinger (NSF DMR-1157490); Y.-Y. Hu (NSF DMR 1508404)


For more information, contact Tim Cross.

Details

  • Research Area: Chemistry
  • Research Initiatives: Energy,Materials
  • Facility / Program: NMR/MRI
  • Year: 2017
Last modified on 6 September 2017