Research into sodium-ion batteries (NIBs) began in the 1970s and ’80s but was overtaken by lithium-ion battery (LIB) research in the 1990s. However, NIBs have recently re-emerged as a potential sustainable and less expensive alternative to LIBs as the demand for lithium drives up its cost, and there is growing concern over the safety of LIB cells, which can be prone to short-circuits and thermal runaway. More…