WISH enables the first neutron diffraction study of an unmodified Li-ion single-layer pouch cell during operation
13 Mar 2026 - Rosie de Laune
For the first time, researchers have been able to study a Li-ion single-layer pouch cell under industrially-relevant operating conditions using neutron diffraction, without the cell needing modification, deuteration or isotope enrichment.
Their experiment was possible due to the unique setup of the WISH beamline at ISIS and provides new opportunities for using the hugely valuable technique to study existing and novel battery materials at scale.
Understanding what is happening inside a battery material while it is charging and discharging is crucial to improving the performance of existing batteries and developing new materials for use in the batteries of the future.
Neutron diffraction is a useful technique for studying battery materials due to its sensitivity to light elements such as lithium, carbon and oxygen, and ability to distinguish between the neighbouring 3d transition metals such as Mn, Fe, Co and Ni. It provides information on the crystallographic transformations that can influence the ways batteries operate and degrade.
Ideally, when studying a cell during operation (known as an (in) operando experiment) through neutron diffraction, the same cell and operating conditions should be used as for standard electrochemical testing. This ensures that the results obtained are directly applicable during realistic practical operation.
However, due to the neutron’s weak interaction with matter, sample volumes for neutron experiments typically need to be notably larger than what is used for standard academic testing of battery materials. Neutrons are also incoherently scattered by hydrogen and adsorbed by the lithium-6 isotope (6Li), both of which are abundantly present in electrochemical cells and many battery materials. These factors mean that, until now, operando neutron (diffraction) experiments have required custom built cells and isotopic substitution/enrichment of hydrogen and lithium. Other studies have relied on larger commercial cell formats for such studies, which are not suitable for systematic iterative investigations due to it being very resource intensive to fabricate at scale.
Not only does it allow for further in-depth studies of existing battery materials, the sensitivity of neutrons to lithium and hydrogen is expected to make this technique useful to study electrolyte species, and to contribute to the development of lithium metal and anode-less batteries.
Ashok Menon, University of Warwick
To address these issues, the researchers from Warwick Manufacturing Group worked with Gabriel Perez, Fabio Orlandi and Pascal Manuel from ISIS, as part of a project funded by the Faraday institution, to use the unique capabilities of the WISH beamline at ISIS.
WISH has a longer-wavelength cold-neutron flux profile and a low pulse repetition rate, which allows the backscattering detector banks to access longer length scales than other diffractometers. This reduces the effects of both incoherent scattering from hydrogen and adsorption from elements such as lithium 6. Being able to access the longer length scales also provides information on structural characteristics that are particularly relevant to the state of charge of a lithium battery.
The team were successful in carrying out an operando experiment on a single layer pouch cell taken straight from the WMG battery scale-up facility, without any modification, deuteration or isotope enrichment, cycled under commercially relevant conditions.
These cells can also directly studied using X-ray diffraction as-is, as demonstrated by measurements at the Diamond Light Source. Their results show that the two techniques bring different insights, illustrating their complementarity. As well as the sensitivity to the elements present in battery materials, neutrons also do not cause any beam-induced sample damage, which may occur in X-ray experiments. Furthermore, the overall size of the neutron beam is orders of magnitude larger than that of X-rays, meaning that a larger area of the sample/cell maybe probed at a time, thereby ensuring a statistically relevant investigation of the cycling-induced changes in the electrodes.
“Being able to perform reproducible joint operando X-ray and neutron diffraction studies directly on the same electrochemically benchmarked pouch cells that can be fabricated at scale opens a lot of exciting avenues for developing diagnostic methods for different battery technologies,” explains Ashok Menon from the University of Warwick.
“Not only does it allow for further in-depth studies of existing battery materials, the sensitivity of neutrons to lithium and hydrogen is expected to make this technique useful to study electrolyte species, and to contribute to the development of lithium metal and anode-less batteries.”
The full paper can be found at DOI: 10.1021/acs.chemmater.5c03201
