Metal-organic framework (MOF)-derived amorphous nickel boride: an electroactive material for electrochemical energy conversion and storage application

• Published in: Sustainable energy & fuels Vol. 5; no. 4; pp. 1184 - 1193
• Main Authors: Tripathy, Rajat K, Samantara, Aneeya K, Behera, J. N
• Format: Journal Article
• Language: English
• Published: London Royal Society of Chemistry 23.02.2021
• Subjects: Amorphous materials; Capacitance; Crystal structure; Crystallinity; Durability; Electroactive materials; Electrochemical analysis; Electrochemistry; Electrode materials; Electrodes; Energy conversion; Energy storage; Flux density; Metal-organic frameworks; Nickel; Nickel oxides; Optimization; Redox properties; Retention; Ruthenium oxide; Storage systems; Supercapacitors; Sustainability; Thermogravimetric analysis; Tuning
• ISSN: 2398-4902; 2398-4902
• DOI: 10.1039/d0se01831g

The search for an efficient single electrode material having both electrochemical energy conversion and storage activities is a cutting-edge approach for sustainability. In this report, an effective chemical redox approach is presented for the tuning of the crystalline and electronic structures of a metal-organic framework (Ni-MOF) to improve its electrocatalytic and charge storage performance. The single step redox approach transformed the crystalline Ni-MOF to amorphous nickel boride (NiB), showing increased exposed catalytic active centers and accessible surface area thereby improving its electrochemical performance. Interestingly, the NiB efficiently catalyzes the OER, delivering a benchmark current density (10 mA cm −2 ) at only 240 mV as well as excellent electrocatalytic durability. On the other hand, it shows a higher value of specific capacitance (2580 F g −1 ) and remarkable energy (72.55 W h kg −1 ) and power (33.43 kW kg −1 ) densities with outstanding cycle life (85.45% retention of the initial capacitance after 5000 cycles). In order to validate the practical application of the material, an asymmetric supercapacitor (ASC) was devised in a Swagelok-type electrode with rGO and NiB as the cathode and anode electrode material, respectively. The rGO//NiB ASC device showed a specific capacitance of 83.33 F g −1 (at 0.5 A g −1 ) with an energy density of 26.04 W h kg −1 at a specific power of 2.08 kW kg −1 with excellent durability (96% specific capacitance retention after 5000 GCD cycles). This synthesis approach realizes the tuning of faradaic redox properties and sheds substantial light on motivating materials researchers to derive MOF-based nanostructures for future energy conversion and storage systems. A single step redox approach that transformed the crystalline Ni-MOF to amorphous nickel boride (NiB) nanostructures showed excellent electrocatalytic (oxygen evolution reaction; OER) and charge storage (supercapacitor) performances.