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

A High-Performance, Low Defected, and Binder-Free Graphene-Based Supercapacitor Obtained via Synergistic Electrochemical Exfoliation and Electrophoretic Deposition Process

An integrated electrochemical exfoliation and electrophoretic deposition (EPD) method is developed to achieve a high-performance graphene supercapacitor. The electrochemical delamination of graphite sheet has obtained a low-defected few-layer graphene adorned with oxygen-containing functional groups. Then, the EPD process produced a binder-free electrode to alleviate the graphene restacking problem. The electrode prepared using a deposition voltage of 5 V exhibits the highest specific capacitance of 145.95 F/g at 0.5 A/g from three-electrode measurement. Moreover, this EPD-prepared electrode also demonstrates superior electrochemical properties compared to electrodes fabricated using PVDF binder. In the real symmetrical cell, the EPD-prepared electrode also shows excellent performance with a high rate capability of 82.31 % (from 0.5 A/g to 10 A/g), high cycling stability of 95.00 % (at 5 A/g) after 10,000 cycles, and rapid frequency response with short relaxation time (τ 0 ${{\tau }_{0}}$ ) of 9.73 ms. These results indicate that this integration method is beneficial to construct a high performance binder-free supercapacitor electrode consisting of low-defected graphene materials, low electrode resistance, and less agglomeration of graphene sheets by utilizing an environmentally friendly process.

Sputtered binder-free Cu3N electrode materials for high-performance quasi-solid-state asymmetric supercapacitors

Developing high-efficiency electrode materials is of great importance in manufacturing supercapacitor devices with superior electrochemical performance. Herein, we for the first time report a binder-free method for controllable growth of Cu₃N electrode materials via magnetron sputtering for supercapacitor applications. Benefiting from their unique polyhedral structure and good electrical conductivity, Cu₃N electrodes can achieve an areal capacity of 90.7 mC cm^-2 at 1 mA cm^-2 and outstanding cycling stability with a capacity retention of 97.4% after 20 000 cycles. In particular, the assembled Cu₃N//active carbon quasi-solid-state asymmetric supercapacitor can exhibit a maximum energy density of 13.2 μW h cm^-2 and a power density of 4.8 mW cm^-2 with an operating voltage of 1.6 V. These remarkable performances demonstrate the great potential of sputtered Cu₃N electrode materials for future energy storage applications.

Synthesis of manganese molybdate/MWCNT nanostructure composite with a simple approach for supercapacitor applications

Recently, magnesium molybdate materials have attracted scientific attention for application in supercapacitor devices due to advantages like low synthesis cost and good redox reactions. Nevertheless, these materials endure low electrical conductivity leading to inferior electrochemical performance. To eliminate this drawback, we prepare a composite powder containing magnesium molybdate and functionalized carbon nanotubes (MMO/C) using a simple process to improve the supercapacitive properties. The results proved an electrostatic interaction between the two components of the composite powder, which contains 18-30 nm magnesium molybdate nanoparticles. A crystal model related to magnesium molybdate powder (MMO) was simulated, illustrating that MnO6 octahedra are formed next to MoO4 tetrahedra. The mesoporous structure of both powders was confirmed whereas the specific surface area of the MMO was enhanced by 69.9% to 36.86 m2 g-1 in the MMO/C powder with more electroactive sites. The higher electrical conductivity of the MMO/C electrode was proved using electrochemical impedance spectroscopy (EIS) results, with the MMO/C electrode achieving a specific capacitance of 571 F g-1 at 1 A g-1 current density, improved by more than 4.5 times that of the MMO. Furthermore, the rate performance and cycling stability of the MMO/C electrode reached 87% and 85.2%, respectively. Finally, a two-electrode energy storage device (MMO/C//AC) was assembled. It reveals a specific capacitance of 94.7 F g-1, a maximum energy density of 29.6 W h kg-1 at a power density of 660.1 W kg-1, and cycling performance of 84.3% after 2000 cycles. As a result, the resulting data demonstrate that the MMO/C electroactive material has promising abilities in capacitive energy storage systems.

Direct Inkjet Printing of Digitally Designed 2D TiN Patterns

TiN is a non-oxidic ceramic widely employed as a hard coating material for cutting tools due to its high thermal and chemical stability. Among all 2D coating techniques, Inkjet printing (IJP) is one of the most promising for the fabrication of layers with customized designs. However, despite its advantages, this process has not been used so far with this material. In this work, we prepared TiN suspensions for their implementation in IJP with a nozzle of 70 μm. A complete study of the ink properties was performed to formulate a suitable ink with a high level of dispersion and to evaluate the jetting during the printing process. Moreover, after a sintering process at 1100 °C under vacuum, a complete hardness analysis of the coated discs was performed, resulting in values ranging from ~4 to 7 GPa, depending on the grid design.

Surface Optimization of Commercial Porous Ti Substrates by EPD of Titanium Nitride

In this work, the infiltration of TiN powders by electrophoretic deposition (EPD) in aqueous media was considered as alternative method to reduce the size craters and the roughness of commercial porous Ti substrates. Ti substrates can be used as suitable supports for the deposition of dense hydrogen separation TiNx-based membranes by physical vapor deposition (PVD) techniques. The influence of various EPD deposition parameters on surface morphology and roughness of TiN-infiltrated substrates were investigated in order to optimize their surface properties. The results suggest that a multi-step EPD procedure is an effective technique for reducing substrate surface defects of commercial porous Ti substrates which could then be successfully used as proper supports for the deposition of dense and defect-free TiNx layers, also aligning the thermal mismatch between the active layer and the porous substrate.