Printable Ta Substrate with High Stability and Enhanced Interface Adhesion for Flexible Supercapacitor Performance Improvement

The existence of supercapacitors with a long calendar life, a superior power density, and a higher mechanical stability is increasingly drawing attention due to their viability to be used as power sources onboard wearable electronics. However, a considerable issue is that upon repeated cycling, an unstable interface between the conducting substrate and the active materials leads to low conductivity and overall poor device performance, thereby hindering its practical applications. Tantalum foil is a potential substrate which can be used in the fabrication of supercapacitors; it has strong corrosion resistive properties, good bendability, and is mechanically stable. These properties make it suitable for use in supercapacitors. Here, a printable tantalum foil substrate with printed carbon particles on its surface is described, showing high adhesion and a greatly improved interface for the fabrication of traditional activated carbon film based supercapacitors. The flexible solid‐state supercapacitors with this printable substrate achieve a higher volumetric capacitance, outstanding energy density, a higher power density, and provide excellent mechanical flexibility. These results indicate that the strategy to use a printable substrate with an enhanced adhesion interface provides an alternative method to achieve highly stable and highly efficient supercapacitors which are ideal to be used in portable devices and flexible electronics. A high‐performance flexible energy storage platform is fabricated using a new electric spark discharge printable method that integrates a carbon film for the first time. Stable interface effect between the conducting substrate and active materials leads to high electrochemical performance and mechanical stability, which is better than traditional carbon‐based supercapacitors.