Efficient hydrogen production and optional power generation through coal-assisted water electrolysis
Ling Fu, Senran Hao, Hailong Liao, Wenrui Liu, Yuan Zhang, Haojie Zhu, Tao Liu, Bin Chen, Heping Xie
Abstract
Green hydrogen production from water electrolysis is hindered by the high energy cost for electrochemical oxygen evolution half reaction. Supplying low-cost fuel to the electrolysis can effectively lower the electrical power required, or even achieve optional power generation during hydrogen production. Herein, we develop coal-assisted solid oxide electrolysis cells to demonstrate this concept, achieving an excellent performance of −400 mA cm −2 at only 0.17 V @850 °C using pyrolysis lignite as the coal source. The co-generation of power and H 2 was also achieved at a current density of 25 mA cm −2 at an average voltage of −0.025 V. We employed a new 3D external anode (Fe-Cu/Ni foam) with expanded reaction sites and high carbon resistance to solve the issue of limited contact between coal and anode and to mitigate the carbon deposits/ash accumulation to further improve the performance. Economic analysis shows excellent competitiveness with a cost of 1.33–2.07 USD/kg H 2 with waste heat resources. This work has demonstrated an economical, efficient, and low-energy technology for hydrogen production and even optional power generation.