Laser Synthesis of MOF-Derived Ni@Carbon for High-Performance Pseudocapacitors
Do Van Lam, Muhammad Sohail, Jae‐Hyun Kim, Hak Joo Lee, Seong Ok Han, Jonghwa Shin, Duckjong Kim, Hyunuk Kim, Seung‐Mo Lee
Abstract
Although nanosizing of multiphase pseudocapacitive nanomaterials could dramatically improve their electrochemical properties, a proper way to simultaneously control both the size and the phase of the pseudocapacitive materials is still elusive. Herein, we employed a commercial CO2 laser engraver to do the transformation of a metal–organic framework (MOF-74(Ni)) into size-controlled Ni nanoparticles (4–12 nm) in porous carbon. The produced Ni@carbon hybrid showed the best specific capacitance of 925 F/g with excellent cycling stability when the particle size is 5.5 nm. We found that the highly redox-active α-Ni(OH)2 is more predominantly formed than the less redox-active β-Ni(OH)2 as the particle size becomes smaller. Our results substantiate that various MOFs could be created into high-performance pseudocapacitive materials with the controlled size and phase. It is believed that the laser-based synthesis could also serve as a powerful tool for the discovery of new MOF-derived materials in the field of energy storage and catalysis.