'It can't be done!' - lessons from operando X-ray studies of real-format pouch cells without windows or Synchrotron

The manufacture of state-of-art Li-ion batteries require the consideration of $/KWh at cell and pack level at end of life (EOL) ie 80% capacity retention after 1000s of cycles. As a result, we need to simultaneously increase cell performance and longevity.

Extending battery lifetimes in state-of-the-art batteries requires an academic understanding of degradation processes within industry-like manufactured cells. Ideally, we would like to directly observe the intercalation reactions directly within the real cells as a function of cycling to trace the origins of degradation. Unfortunately, most operando studies of these batteries employ either ½-coin cell configurations and/are compromised cells to cater the geometry of the X-ray experiments.

Here, I will summarise our recent developments to employ industry-like cells with in-house x-ray diffraction/absorption and electron microscopy to track the degradation in Ni-rich NMC (NMC811) // graphite single-layer pouch cells after prolonged cycling.1 This new capability enables us to examine the fundamental intercalation reactions occurring in real cells under drive cycles for electric vehicle applications. As a result, it provides new insight into the origin of oxygen loss induced degradation. In state-of-art Ni-rich cell chemistries.[1,-4]

[1] PRX Energy (2024, in press) – 10.26434/chemrxiv-2023-zs9kp-v2
[2] Chemical Reviews 122 (2022), 5641-5681
[3] Joule 7 (2023) 1623-1640
[4] ACS Energy Letters 8 (2023), 5025-5031