The commercial demand for high-capacity batteries is driven by the 300-mile driving range that is expected for electric vehicles, which equates to a cell-energy density of 300 Wh kg-1 and a material specific capacity of ~200 mAh g-1. Nickel-manganese-cobalt (NMC-811) is a cathode material that can achieve a practical capacity of 180-200 mAh g-1, but one obstacle to its commercialisation is the long synthesis durations and its sensitivity to reaction conditions. This thesis investigates alternative synthesis methods for NMC-811 using microwave technology to reduce the reaction time, energy
consumption during the reaction and increasing the throughput of NMC-811 synthesis making its synthesis procedure more environmentally friendly. Specifically, the application of a microwave reactor to the synthesis of Ni0.8Mn0.1Co0.1(OH)2 precursor is investigated, as well as the application of a microwave furnace during the calcination of the precursor to form the cathode active material, LiNi0.8Mn0.1Co0.1O2. Due to the alternative mechanism behind the heating of the system, the
crystallographic, morphological, and electrochemical properties of the resultant materials were examined to establish any differences between the conventional and microwave syntheses.
In this thesis, Chapters 1 and 2 introduces the background literature behind lithium-ion batteries, microwave heating, experimental techniques, and other related topics. Chapter 2 also details the experimental methods conducted in this work. Chapter 3 investigates an alternate calcination procedure that utilises a microwave furnace and an alternative lithium source, Li2O2 to optimise the synthesis pathway for microwave heating. Chapter 4 validates this alternative calcination pathway
using electrochemical half-cell testing to evaluate the capacity yielded from the cells, the capacity retention, impedance, and diffusivity of samples to evaluate the optimised microwave calcination procedure. Chapter 5 discusses the hydrothermal synthesis of Ni0.8Mn0.1Co0.1(OH)2 using a microwave reactor and the optimisation of this reaction. Chapter 6 develops the novel microwave-assisted co-precipitation synthesis of Ni0.8Mn0.1Co0.1(OH)2, involving the design and commissioning of the Microwave Stirred Tank Reactor (MiSTR). Chapter 7 and 8 concludes the findings in this work and discusses the future work associated with this research; namely the addition of oxygen to the microwave furnace system during calcination and further development of the microwave stirred tank reactor and developing the design and operating procedure.
