Laser-induced nitrogen-doped hierarchically porous graphene for advanced electrochemical energy storage

Abstract

Development of one-step processes combining hierarchical porous architecture with heteroatom doping control has remained a challenge. This is especially important for structure-engineered graphene materials as high performance active electrodes for energy and advanced applications. Herein, we present a facile and general approach for synthesizing patternable, nitrogen-doped and hierarchical porous graphene from graphene oxide/urea mixture using high-repetition picosecond laser in ambient air. Impressively, the highest areal capacitance of laser-induced nitrogen-doped graphene (LING) is 60.7 mF/cm2, which is about 3 times that of undoped porous graphene. After 25,000 consecutive cycles of galvanostatic charge-discharge at a current density of 10 mA/cm2, the optimized LING electrode maintained 98.7% of its original capacitance. Most importantly, the as-prepared LING electrode material has high energy and power density due to the synergistic effect of hierarchical porous structure, nitrogen-doping and engineering defects. The proposed laser one-step synthesis of LING may also be applied to other heteroatom-doped hierarchical porous graphene-based electrodes for high-performance electrochemical energy storage.