Iron-based Rechargeable Batteries for Large-scale Battery Energy Storage

It is a global challenge to develop green, sustainable power source for modern portable devices, and stationary power generation. Energy storage systems (ESS) can improve the stability and quality of the power grid. Moreover, ESS can be used for peak shaving, integration viable renewable sources to the electricity network. Several ESSs technologies are existing, electrical, thermal, mechanical, and electrochemical storage technologies. This thesis proposes the potential of iron-based electrode batteries such as Nickel-Iron (NiFe) batteries to be implemented for large-scale grid power. This proposal applies to other types of iron-based electrode rechargeable batteries. Iron-based electrode batteries such as Ni-Fe batteries are particularly attractive and compelling to utilise the energy generated from renewable resources. NiFe battery clearly stood out in view of their cost-effective, robust, and eco-friendly materials. Numerous problems have hindered their developments. Those limitations are poor discharge capability and charge efficiency. In fact, the performance of these batteries is drastically reduced by the parasitic evolution of hydrogen. The key is to develop electrode/electrolyte electroactive materials as additives to improve the performance of the battery. This approach has been successful in many rechargeable batteries. In this thesis, investigation of several electrode/electrolyte additives for advanced NiFe batteries is conducted. In this, an effort is made to improve the performance of the NiFe battery by including different electrode and electrolyte additives to suppress the hydrogen evolution (HER) despite the fact that the addition of various percentages of Bi2S3, FeS, K2S, CuSO4 or other sulfide elements to the electrode and electrolyte is a very effective method of suppressing the HER. In this study, paste-type and hot-pressed types electrode samples were used to produce the electrode samples. Galvanostatic charge/discharge cycling, and cyclic voltammetry were used to investigate the electrochemical properties of the electrode samples. The prepared and cycled electrode samples were characterised a variety of physical techniques including X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It has been found in this study that, the presence of iron sulfide in the electrode has a real incidence on increasing the reversibility and performance of the electrode samples than using copper alone. Therefore, this improves the overall performance of NiFe batteries; however, due to the fact that we have used commercial grade reactants and materials, this technology definitely has the potential to be further developed in the long run and could provide a cost-effective solution to large-scale energy storage.