STRATEGIES TO IMPROVE THE CATHODE PERFORMANCE FOR MnO2/Zn AND NiMH BATTERIES

Date

2024-1-08

Author

Darıcıoğlu, Necdet Özgür

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This thesis addresses the pivotal role of Energy Storage in our modern world, focusing on MnO2/Zn and NiMH alkaline batteries. Two primary objectives guide this research: optimizing MnO2 cathode composition for enhanced rechargeability and replacing cobalt with cost-effective carbon in NiMH battery cathodes for improved performance and affordability. To achieve the first objective, a combinatorial approach using magnetron sputtering is adopted to modify MnO2 structure with Bi, Na and Ni. Results show promising cathode compositions, such as Bi0.08Na0.39Ni0.09Mn0.44Ox, exhibiting reversible characteristics and outperforming pure MnO2 cathodes by over double in terms of reversible capacity. In the context of NiMH battery cathodes, conventional slurry methods are employed with various carbon additives and blending techniques. The study identifies challenges in achieving optimal performance, highlighting the importance of selecting appropriate carbon additives. The best-performing cathode combines carbon black with plasma black using the dispersion method. However, all carbon bearing cathodes fall short of cobalt bearing cathode performance. Electrochemical and structural investigations provide insights into the challenges faced, revealing issues with poor contact, insufficient surface coverage, and the absence of cobalt. The study sheds light on the development of cobalt free cathodes, emphasizing the need for improved electrode production methods and new additives to address challenges such as γ-NiOOH formation and oxygen evolution reaction. In conclusion, the research contributes valuable findings for enhancing the electrochemical performance and cost-effectiveness of MnO2/Zn and NiMH alkaline batteries, offering potential solutions for advancing energy storage technologies.

Subject Keywords

Alkaline battery, MnO2 cathode, Combinatorial approach, Co-free cathode, NiMH battery

URI

https://hdl.handle.net/11511/108278

Collections

Graduate School of Natural and Applied Sciences, Thesis