Conformal atomic layer deposition of RuOxon highly porous current collectors for micro-supercapacitor applications.

3D porous electrodes have been considered as a new paradigm shift for increasing the energy storage of pseudocapacitive micro-supercapacitors for on-chip electronics. However, the conformal deposition of active materials is still challenging when highly porous structures are involved. In this work, we have investigated the atomic layer deposition (ALD) of ruthenium dioxide RuO2on porous Au and Pt architectures prepared by hydrogen bubble templated electrodeposition, with area enlargement factors ranging from 400 to 10 000 cm2/cm2. Using proper ALD conditions, a uniform RuO2coverage has been successfully obtained on porous Au, with a specific electrode capacitance of 8.1 mF cm-2and a specific power of 160 mW cm-2for a minute amount of active material. This study also shows the importance of the chemical composition and reactivity of the porous substrate for achieving conformal deposition of a ruthenium oxide layer.

Effects of the Formulations of Silicon-Based Composite Anodes on their Mechanical, Storage, and Electrochemical Properties.

In this work, the effects of the formulation of silicon-based composite anodes on their mechanical, storage, and electrochemical properties were investigated. The electrode formulation was changed through the use of hydrogenated or modified (through the covalent attachment of a binding additive such as polyacrylic acid) silicon and acetylene black or graphene sheets as conducting additives. A composite anode with a covalently grafted binder had the highest elongation without breakages and strong adhesion to the current collector. These mechanical properties depend significantly on the conductive carbon additive used and the use of graphene sheets instead of acetylene black can improve elongation and adhesion significantly. After 180 days of storage under ambient conditions, the electronic conductivity and discharge capacity of the modified silicon electrode showed much smaller decreases in these properties than those of the hydrogenated silicon composite electrode, indicating that the modification can result in passivation and a constant composition of the active material. Moreover, the composite Si anode has a high packing density. Consequently, thin-film electrodes with very high material loadings can be prepared without decreased electrochemical performance.