Magnetic Resonance Imaging of Sodium-Ion Batteries

This chapter explores the use of 2D 23 Na MRI and 23 Na nuclear magnetic resonance (NMR) spectroscopy, in combination with 3D 1 H magnetic resonance imaging (MRI) in investigating dendrite growth in a sodium metal cell and the evolution of sodium species in a sodium-ion full cell. In situ 23 Na NMR spectroscopy has been used to investigate sodium metal deposition and the formation of high-surface-area mossy and dendritic sodium microstructures during cell cycling, identify different sodium crystallographic sites, and sodium states in hard carbon materials. The formation of sodium dendrites is an area of interest in NIBs and was investigated in the sodium metal cell, during galvanostatic plating. Future cell designs should aim to minimize this excess electrolyte in addition to providing even compression across the battery. Formation of metallic dendrites has been observed using 23 Na MRI, and their distribution and shape in 3D confirmed using 1 H MRI.