Laser direct writing of heteroatom-doped porous carbon for high-performance micro-supercapacitors

Simultaneously improving the specific surface area, pore size distribution, heteroatom doping, and electrode/electrolyte interface of carbon materials for high-performance supercapacitors or micro-supercapacitors (MSCs) is difficult, especially in one-step laser direct writing process. This study demonstrates a general and effective strategy for the first time to prepare heteroatom-doped porous carbon structures with high specific surface area, narrow pore size distribution, heteroatom doping, and improved electrode/electrolyte interface, through one-step laser direct writing on precursor-incorporated polyimide (PI) films, which endow the MSC with dramatically improved capacitive performance. The typical MSC prepared on the PI/H₃BO₃ film exhibits an ultrahigh specific capacitance of 65.7 mF/cm² at 0.05 mA/cm², which is more than 5400% of the 1.2 mF/cm² and 250% of the 25.5 mF/cm² for MSCs prepared on as-prepared H₃BO₃-free PI film and commercial PI film, respectively. Moreover, the MSC shows excellent cycling stability (>50000 cycles), outstanding flexibility (foldable), long-term stability (>6 months), and the capability of delivering high voltage and energy by connecting in series and parallel, which make it a promising energy storage component in next-generation portable electronics. What's more, P-doped porous carbon MSCs and fluorinated porous carbon MSCs with high capacitive performances were also demonstrated by incorporating H₃PO₄ or NaBF₄ into PI films followed by the same laser direct writing process, suggesting the generality of this approach. The strategy proposed in this work paves a new avenue for modulating structures and components and improving electrode/electrolyte interface of carbon materials for high-performance supercapacitors.