Acknowledgment Acknowledgment Acknowledgment Acknowledgment This research is financially supported by the ANR within the DENSSCAPIO project (ANR-17-CE05-0015-02). The authors also want to thank the French network on electrochemical energy storage (RS2E) for the financial support. The French RENATECH network is greatly acknowledged for the use of microfabrication facilities. Associated Professor Dr Christophe Lethien wants to thank Professor Thierry Brousse and the "Institut des Matériaux de Nantes" for welcoming him as a visiting professor in 2018. Jean Louis Codron and Xavier Wallart are greatly acknowledged for the XPS measurements.