Electrophoretic deposition of binder-free TiN nanoparticles to design 3D microstructures. The role of sintering in the microstructural robustness of supercapacitor electrodes

TiN is herein used as an example to elucidate that a sintering treatment should be considered as a relevant variable to discuss charge storage mechanisms, charge transfer resistances and others important electrochemical aspects of the non-oxidic supercapacitor electrodes. Binder-free TiN nanocoatings with low charge transfer resistance (<2 Omega), rapid response with diminutive tau(0) (10 ms) and high electrochemical stability displayed competitive capacitance values (120F.g(-1) at 2A.g(-1)) as high-performance supercapacitor electrodes. The sintered electrodes finally improve the nanostructure connectivity and preserves the microstructural integrity, reinforcing the adhesion and joining between the collector and the electroactive material. A gradual degradation was observed for as-deposited coatings, leading to capacitance losses during cycling due to the chemical instability of the pre-sintered TiN coatings, while the full-connected electroactive nanostructure resulting from the thermal treatment leads to an enhancement of the electrochemical response. The robust structure of the sintered electrode helped to prevent chemical/structural damages avoiding retention capability losses. The processed coatings with designed microarchitectures onto non-carbonaceous collector allows distinguishing the effects of each charge-storage mechanism, both capacitive and faradaic contributions of the electroactive material. Electrophoretic Deposition (EPD) is the selected technique to prepare nanostructured films on the Ni foams from TiN nanoparticles (TiN-NPs) suspensions. FESEM and electrochemical results confirm that TiN-NPs full-cover the 3D foams and the first layers, in direct contact with the substrate, consolidate during the EPD process due to the elevated voltage applied to the on growing layer. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

TiN is used as an example to discuss the importance of sintering treatment in non-oxidic supercapacitor electrodes. Binder-free TiN nanocoatings show low charge transfer resistance, rapid response, and high capacitance values, making them high-performance electrodes. Sintered electrodes improve nanostructure connectivity, prevent chemical/structural damages, and enhance electrochemical response compared to non-sintered coatings.