In operando small-angle neutron scattering (SANS) on Li-Ion batteries

Small-angle neutron scattering is a tool providing information on nanostructures of objects in the order of 1-300 nm. In this experiment a pouch bag lithium ion battery cell was investigated with SANS ex situ, in situ and in operando during charging and discharging. LiNi_0.33Mn_0.33Co_0.33O₂ was used as cathode and graphite as anode material. The small-angle neutron scattering measurements were performed on the SANS-1 instrument at the FRM II neutron source of the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching, Germany. Ex situ measurements of components of the cell as well as static in situ and dynamic in operando SANS experiments were performed with a complete Li-ion pouch bag cell. The cell was charged and discharged twice with C/3 and small-angle neutron scattering data were collected during the measurements. The observed intensity data were then evaluated and changes of the total scattering in the measured Q-range are correlated to the lithiation processes occurring inside the cell. Thus we can show that SANS can be used as a tool to monitor kinetic processes in Li-ion batteries in operando and non-destructively.