Manganese Based Low-cost Battery Systems for Scaled-up Energy Storage Applications

Challenges such as material availability, supply chain security, high costs, short cycle life,  limited storage duration, and thermal safety issues have become more pronounced for  current electrochemical batteries. As a response, new advanced battery materials and  systems are emerging to mitigate these drawbacks. Among these, flow batteries, aqueous  batteries, and sodium-ion battery systems stand out as potential solutions for future energy  storage. 

In this thesis, I will primarily focus on the aqueous battery system and the sodium-ion  battery system for cost-effective energy storage systems. Specifically, in chapters 3 and 4  we will examine the correlation between the electrochemical performance of the second  electron reaction of the aqueous alkaline MnO₂ battery and the volume of the electrolyte,  the carbon material, and the active material particle size. Moreover, the bismuth-phased  material was synthesized via different chemical methods with their performance evaluated.  Lastly, the feasibility of an affordable iron-MnO₂ based battery system for energy storage  will also be investigated.  

In Chapter 5, we turn our attention to a P2-phase sodium manganese oxide cathode system  for use with non-aqueous electrolytes, to identify methods that could enhance its cycling  stability. We discovered that bismuth-doping at a small level could considerably increase  the cycling stability of this system by suppressing the manganese dissolution. This material  also demonstrated enhanced stability when exposed to moisture conditions, indicating its  potential to be used as a cathode material for future energy storage systems.

 Chapter 6 will address the issue of thermal stability in batteries. By introducing a novel  battery electrolyte solvent, glycerol triacetate (GTA), we propose a solution for enhancing  the high-temperature stability of the battery. GTA-based electrolytes have shown promising  performance for high-temperature applications in lithium-ion battery systems with LFP,  NCM, and CFx cathodes. GTA also effectively suppressed heat generation within the cell  when subjected to damage or abuse use cases. This thermally more stable electrolyte  system could also be potentially used in stationary storage battery systems.