In this work published in the Journal of the Electrochemical Society, we studied the effect of cold-pressing and spark-plasma sintering (SPS) processing on the Na3OBr sodium-rich anti-perovskite solid electrolytes was studied. SPS was found to reduce the interfacial impedance by 3 orders of magnitude. The much lower conductivity of Na3OBr compared to the lithium analogue is attributed to the significantly higher defect formation energies. This work is led by the Laboratory of Energy Storage and Conversion of Prof Shirley Meng. Zhi Deng and Prof Ong are co-authors.
In this follow-on work as part of the NECCESS EFRC, a combination of hard and soft x–ray photoelectron and absorption spectroscopy techniques to depth profile solid state synthesized LiVOPO4, a promising multi-electron electrode for rechargeable lithium-ion batteries. This work confirms that limited kinetics in the high voltage regime are responsible for the inability to fully intercalate 2 Li in this material. The evolution from LiVOPO4 to Li2VOPO4 via the intermediate phases as predicted in our previous work (“Thermodynamics, Kinetics and Structural Evolution of ε-LiVOPO4 over Multiple Lithium Intercalation”) is confirmed by O K–edge absorption spectroscopy and DFT calculations. Yuh-chieh Lin and Shyue Ping Ong are co-authors in this work.