Ni-B-based Materials for Electrochemical – Thermally-Activated Chemical (E-TAC) Water Splitting

events hall

Mr. Yossi Halpern - MSc candidate

04.08.2022

David Wang Auditorium, 3rd floor Dalia Meidan Bldg.

14:30

Electrochemical-Thermally-Activated Chemical (E-TAC) water splitting is a membrane-less technology for “green” Hydrogen production, which decouples the hydrogen and oxygen evolution reactions, leading to an increase in energy efficiency. Conventional E-TAC anodes are based on the reversible transition between the crystalline phases, β-Ni(OH)2 β-NiOOH. This phase transition could be one of the kinetic hindrances that decrease the charge capacity in the E-TAC process.

To address this challenge, amorphous nickel-boron-based anodes were synthesized via a chemical reduction method, and their feasibility for the E-TAC process was studied. The increase of the electrode capacity (up to 300 C/g) in the course of slow galvanostatic charge/discharge suggested the “shrinking core” model of the Ni-B-based spherical particles into layered crystallite Ni(OH)2 platelets, which was confirmed using ex situ TEM imaging. Electrochemically pre-activated samples demonstrated E-TAC charge capacity values up to 700 C/g. During the E-TAC cycles, the TAC regeneration time was found to increase significantly from cycle to cycle, which was shown to be directly correlated with the crystallinity growth by means of ex situ XRD. It was revealed that the amorphous structure of the as-prepared material undergoes a full transformation to form thin hexagonal platelets of Ni(OH)2, which is an undesirable outcome for the E-TAC process but could be potentially applied as a new synthetic technique for growing single-crystal hexagonal particles.

BIO

  • M.Sc. candidate in the Electrochemical Materials and Devices group under the supervision of Prof. Avner Rothschild.
  • Double B.Sc. in Physics and Materials Science Engineering from Technion.
  • Prior to the M.Sc. studies worked as a research and development engineer of advanced flexible solar cells in Apollo Power.

Advisor: Prof. Avner Rothschild