Title : Thin ion-conducting membranes for energy technologies: Advanced conformal deposition by electrochemistry Philippe Knauth
Electrochemical synthesis is a powerful tool for the preparation of conformal, thin solid electrolyte membranes directly on the electrodes, particularly with complex shapes, such as nanotubes, nanowires etc.
Such separators should present the highest possible conductivity by the electrochemically active ions, negligible electronic conductivity, combined with high chemical and mechanical stability.
These requirements drive our development work: we use aromatic polymers, given their excellent mechanical properties (large stiffness and strength), which are decisive for a high durability of the separators and the devices. Single-ion conductivity is assured by grafting the counter-ions on the polymer chain (ionomers).
The talk will present examples of electrodeposition of ionomer membranes and report structural, microstructural and electrical properties of the ionomers, including relevant applications, such as Li microbattery cycling data.
1. Cation-conducting membranes
We synthesized several ionomers containing grafted sulfonate groups. These ionomers (including poly(styrene sulfonate), PSS) can be used for proton exchange membrane fuel cells or enzymatic fuel cells and Li batteries.
2. Anion-conducting membranes
These ionomers contain quaternary ammonium as fixed cationic groups. They can be applied for example in hydroxide exchange membrane fuel cells, enzymatic fuel cells or solid-state water electrolysers.
Thin ionomers separators are a valuable asset for the realization of micropower devices, especially microbatteries and microfuel cells. Furthermore, anodic and cathodic deposition conditions were explored, which opens perspectives for the realization of deposits on various semiconducting substrates and simultaneous or sequential co-deposition with noble or non-noble metals for the realization of catalytic electrodes.