The In-situ Characterization of Fast-charging Degradation Modes in Li-ion Batteries Using High-resolution Neutron Imaging

Extreme fast charging (XFC) of lithium-ion batteries (LIBs) in 10 minutes is one of the main goals of the US Advanced Battery Consortium for low-cost, fast-charged electric vehicles by 2023. However, existing LIBs cannot achieve these XFC goals without significant capacity fade over cycling due to complex XFC degradation modes. One of the key XFC failure mechanisms is dead Li plating on the graphite anode. While numerous methods have detected Li plating, they lack three-dimensional non-invasive visualization of dead Li on graphite anodes in full cells during battery cycling. Herein, we demonstrate the viability of high-resolution (spatial resolution: 10–15 μm) neutron micro-computed tomography (μCT) for in-situ characterization of dead Li on graphite anodes (thickness: ~130 μm) in full cells containing NMC cathode, that were cycled at 1C and 6C.