Laser-induced sulfurization of nickel-based metal-organic frameworks for highly stable phase-engineered energy materials

Abstract

Multiphase metal sulfide nanoparticles are of great importance for high-performance electrochemical energy storage devices, yet a proper synthesis method remains as elusive as ever. Here, we showed that ultra-small multiphase nickel sulfide nanoparticles embedded with conductive graphitic carbon can be easily prepared within a few minutes via laser irradiation onto a sulfur-impregnated nickel-based metal–organic framework (MOF-Ni). The phase of the resulting nickel sulfide nanoparticles (i.e., Ni3S2 and αNiS) was able to be tuned by changing the reactant ratio. We found that the carbon derived from the MOF plays a thermodynamically critical role in the formation of nickel sulfide nanoparticles. The carbon composite with 61 wt% Ni3S2 presented the highest specific capacity of up to 800 C/g and excellent cycling stability, thanks to the engineered multiphase and high porosity. Hybrid supercapacitors made of the composite showed a high energy density of 42 Wh/kg with excellent cycling stability of 96 % over 10,000 cycles. Our study demonstrated that the laser-induced sulfurization method could be an effective method to synthesize various phase-engineered metal sulfide nanoparticles supported on graphitic carbon out of numerous MOFs.