Powering EV Battery Research With X-Ray Diffraction Analysis Our expertise

Converting the battery market’s potential into hard profit is not guaranteed, though. Much will depend on manufacturers being able to make crucial breakthroughs in areas such as cost, reliability, and charging time.

With battery technology evolving day by day, manufacturers need to work hard to convince customers and end-users that their innovations meet the highest standards for safety as well as performance. The supporting battery technology needs to offer higher levels of performance, at less weight, and with greater energy density. Solutions need to be delivered quickly and affordably, at a scale never seen before.

A major issue when developing battery materials with high energy densities is the capacity for degradation during cycling. Causes of battery degradation include particle cracking, lithium retention in electrodes, electrolyte degradation, lithium-plating, and dendrite formation. Understanding these battery degradation mechanisms and limiting them is, therefore, an important part of successfully developing new battery materials.

Research into materials for batteries and energy storage is a hot topic. X-ray diffraction (XRD) offers a rare insight into the material changes at the atomic scale. Several research themes related to materials research for battery technologies make use of X-ray methods.

Cathode materials are usually synthesized using co-precipitation and solid-state fusion. Crystalline quality plays an important role in the overall performance of the battery in terms of discharge capacity and lifetime. For example, good crystallinity tends to favor better cyclic stability.

However, a higher discharge capacity is observed in less crystalline or even amorphous materials. X-ray powder diffraction, especially in combination with pair distribution function (PDF) studies, is a useful technique for exploring crystallinity, lattice disruption, and grain size.

A variety of cathode, ion, anode, and electrolyte materials are investigated to optimize the energy costs and gains for new battery designs. The suitability of new materials as electrodes is dependent upon their crystal structures and how well ion species can be taken up and released by the electrode material.

These crystal structures and the extent to which intercalation causes phase changes or strain in the host lattice with charge and discharge cycle are often studied using X-ray diffraction.

Large improvements in charging, discharging speed, and efficiency can be made by increasing the surface areas of the anodes and cathodes. Complex interpenetrating phases and nanostructured surfaces are investigated, such as films of nanowires, nanoparticle arrays, or porous materials.

At the macroscopic level, the electrodes may be sheets that are multi-layered and coiled around each other as is the case for AA or pencil batteries. XRD, in-situ diffraction, small angle X-ray scattering (SAXS), PDF, and computed tomography can explore these micro and macro structures in greater detail.

The repeated transfer during charges carrying ions in and out of the electrode structures puts strains on the unit cells and the fabric of the electrodes. This can induce phase changes in the crystal structures. Deterioration of performance is most commonly due to the structural defects that can build up in the electrodes hindering the free movement of ions.

Abrupt lattice parameter changes can sometimes also cause particle cracking irreversibly degrading discharge capacity. The non-destructive XRD methods can be used in combination with dedicated in situ stages to directly observe charge and discharge reactions in battery coin, pouch, or electrochemical cells.