1. Nikolina Makivić, LEM Laboratory, Paris University, Paris, France CSE Laboratory, Collège de France, Paris, France, France
To enable higher input of renewable energy into our grid system, increase in gird storage capacity is urgently needed. One way to reach this goal is through development of an aqueous rechargeable proton “rocking chair” battery, relying on proton as a small size and light weight charge carrier, enabling fast charge/discharge and long cycling, as well as aqueous electrolytes to ensure safety, high ionic conductivity and eco-friendliness.
In the present work, titanium dioxide (TiO2) has been investigated as possible candidate for proton insertion anode material in aqueous electrolytes, using well-defined and highly reproducible nanostructured electrodes made of the pure material as model electrodes. The reversible proton-coupled charge storage occurring at such nanostructured electrodes was thoroughly investigated as function of both intrinsic parameters, such as the TiO2 crystallinity, as well as extrinsic parameters, notably the electrolyte composition and pH. First, the influence of the electrolyte composition and pH has been studied at amorphous TiO2 electrodes by comparing reversible proton insertion in buffered and unbuffered aqueous electrolytes. This study revealed the pH-dependence of the proton-coupled charge storage process over the entire pH-range of water as well as the benefit of buffered electrolytes to stabilize the insertion/disinsertion potential and reduce potential hysteresis upon cycling. Next, the influence of the active material crystallinity was investigated by comparing proton-coupled charge storage at amorphous and anatase TiO2 electrodes. Reversible proton insertion was demonstrated to be a bulk charge storage process at both electrodes, with the crystallinity of the material only influencing the energetic but not the dynamic aspects of the process. Besides, reversible proton insertion was evidenced much faster than lithium-ion.
Still, we conclude that TiO2 is not the ideal anode material for a rocking chair proton battery, due to side reactions such as competitive hydrogen evolution as well as acid dissolution. However, the fundamental knowledge gained from the present study remains of primary interest by providing a comprehensive framework for investigation of reversible proton insertion over a wide range of active materials.
Ključne reči :
Tematska oblast:
SIMPOZIJUM A - Nauka materije, kondenzovane materije i fizika čvrstog stanja
Datum:
25.06.2024.
Contemporary Materials 2024 - Savremeni Materijali
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