Aerosol Jet-Printed LFP Cathodes with Bimodal Pore Distribution Improve the Rate Capability of LIB Cells

The electrochemical performance of an aerosol jet (AJ)-printed lithium iron phosphate cathode versus an equivalent tape-cast (TC) cathode was evaluated. Rate capability and long-term cell testing demonstrated that at similar mass loadings and thicknesses, the AJ-printed cathodes achieved higher discharge capacities than the TC cathodes. Electron microscopy and X-ray tomography showed a bimodal pore network for the AJ-printed cathode; larger Li-ion-conducting channels were visible at the electrode surface, while a denser cathode structure (akin to a TC cathode) was present near the current collector. Electrochemical impedance calculations revealed that this bimodal pore distribution endowed AJ-printed cathodes with approximately 30% more electrochemically active surface area than their TC cathode counterparts.