Neutron Transport and Layer-Resolved Radiation Effects in Potassium-Ion Cells with Organic and Inorganic Cathodes Under Space-Relevant Irradiation

The neutron response of potassium-ion batteries containing organic electrode materials remains insufficiently understood, particularly for applications in radiation environments. In this work, a multilayer Geant4 model of a CR2032 potassium-ion cell with a TPHATP composite cathode was developed and compared with a geometrically equivalent LiFePO4 reference model. Prompt fission neutron spectra from ENDF/B-VIII.0, JEFF-3.3, and JENDL-5 were used to evaluate neutron transmission, reflection, layer-resolved energy deposition, NIEL, secondary particle production, and displacement-related quantities. The TPHATP-based cell showed a stronger directional asymmetry in neutron transmission and reflection, associated with the asymmetric layer sequence and the larger fraction of light elements in the organic cathode and electrolyte-containing components. Despite differences in individual particle yields and spectral characteristics, the TPHATP and LiFePO4 models retained broadly similar dominant interaction mechanisms. These results characterize neutron transport and layer-resolved radiation response in the complete cell architecture but do not establish electrochemical radiation tolerance, which requires molecular-scale modelling and experimental validation.