SWNTs for Enhancing Performance and Sustainability of Electrochemical Energy Conversion Devices

Drastically increasing demand for various energy conversion and storage devices poses a tremendous pressure for improving their architecture to meet circular economy principles. This stems from already recognized mismatch between the anticipated demand for nonrenewable minerals and their supply for constructing these devices. Electrodes where electrochemical reactions occur are one of the decisive components for achieving high efficiency and long lifespan in each electrochemical energy conversion device despite of their widely different characteristics. Thus, development of efficient and durable electrodes which enable reduced utilization of critical elements is essential.<br/>Single-walled carbon nanotubes (SWNTs) featured by such desired properties as high electrical conductivity and excellent mechanical and (electro)chemical durability appear as an attractive electrode component for striving for the above-mentioned goals. Here, we present different approaches for preparing 3D SWNT containing composite electrodes for lithium batteries and hydrogen reactions in electrolysers and fuel cells. Our investigations focus on understanding implications of incorporating SWNTs in the electrodes. The origin of the favorable properties and effects brought by SWNTs have been investigated using various structural analysis methods and in-situ electrochemical characterizations. The relevance of adding SWNTs in the composite electrode structure is verified by integrating the electrodes laboratory scale electrochemical cells which are subjected to testing conditions relevant to end applications.<br/>The main benefits of SWNTs incorporation in lithium batteries include improved cycle life and energy efficiency [1. 2], which is essential from both economic and sustainability perspective. On the other hand, for hydrogen economy electrodes utilizing efficiently scarce and valuable nonrenewable metals for electrolyzing the hydrogen conversion reactions are inevitably required. Utilizing SWNTs to support the catalytically active noble metals enables efficient metal utilization while hindering ageing [4-5].<br/> <br/> <br/>[1] S. Mousavihashemi, E. M. Khabushev, J. Lahtinen, A. R. Bogdanova, I. V. Novikov, D. V. Krasnikov, A. G. Nasibulin, T. Kallio, A binder-free Nickel-Rich cathode composite utilizing low-bundled single-walled carbon nanotubes, A binder-free Nickel-Rich cathode composite utilizing low-bundled single-walled carbon nanotubes, Advanced Materials Technologies (2024) 2301765.<br/> <br/>[2] S. Hamed, F. Obrezkov, S. Huotari, M. Colalongo, S. Mousavihashemi, T. Kallio, Optimized NMC622 electrodes with a high content of the active material: A comprehensive study, J. Power Sources 608 (2024) 234549.<br/> <br/>[3] F. S. M. Ali, R. L. Arevalo, M. Vandichel, F. Speck, E.-L. Rautama, H. Jiang, O. Sorsa, K. Mustonen, S. Cherevko, T. Kallio, Hydrogen Evolution in Alkaline Medium on Intratube and Surface Decorated PtRu Catalyst, Applied Catalysis B: Environmental, 315 (2022) 121541.<br/> <br/>[4] O. Sorsa, R. Backhouse, S. Saxelin, T. Rajala, H. Jiang, P. Kauranen, T. Kallio, Optimization of Pt Nanowires Supported on Single-Walled Carbon Nanotubes as a Cathode Catalyst in Polymer Electrolyte Membrane Water Electrolyser, International Journal of Hydrogen Energy 45 (2020) 19121.<br/> <br/>[5] T. Rajala, R. Kronberg, R. Backhouse, M. E. M. Buan, M. Tripathi, A. Zitolo, H. Jiang, K. Laasonen, T. Susi, F. Jaouen, T. Kallio, A platinum nanowire electrocatalyst on single-walled carbon nanotubes to drive hydrogen evolution, Applied Catalysis B: Environmental 265 (2020) 118582