내부저항 분석 기반 통합형 미생물 전기화학 시스템 개발 및 그린수소 생산 = Development of an Integrated Microbial Electrochemical System for Green Hydrogen Production Informed by Internal Resistance Analysis

다국어 초록 (Multilingual Abstract)

Microbial electrolysis cells (MECs) offer a promising approach for green hydrogen production from wastewater, yet optimal operating voltage determination remains a critical challenge. This study employed electrochemical impedance spectroscopy (EIS) to analyze internal resistance components and identify the optimal operating voltage of 1.0 V, where charge transfer resistance was minimized. Subsequently, an integrated system combining parallel-connected microbial fuel cells (MFCs) with MEC was developed for autonomous hydrogen production. Ten MFC units connected in parallel demonstrated stable performance with an open circuit potential of 0.62 V and maximum current of 21.61 mA. The generated electricity was managed through a power management system (PMS) with battery integration. In direct connection mode (MFC-PMS-MEC), hydrogen production rate reached 0.08 m³/m³/d at 0.3 V. With battery assistance at the EIS-identified optimal voltage of 1.0 V, the system achieved 0.66 m³/m³/d, representing an eight-fold improvement. The PMS exhibited 76% energy conversion efficiency. These results demonstrate that EIS-based electrochemical characterization provides crucial insights for optimizing MEC performance, and the integrated MFC-MEC system offers a feasible pathway toward self-powered green hydrogen production from wastewater.

목차 (Table of Contents)

• 1. Introduction 1
• 1.1 Green Hydrogen as a Key Solution for Carbon Neutrality 1
• 1.2 Microbial Electrochemical Technologies for Biohydrogen Production from Wastewater 2
• 1.3 Applied Voltage Optimization and Electrochemical Characterization in Microbial Electrolysis Cells 5
• 1.4 Development of MFC Stack Technology and Self-Powered MFC-MEC Integrated Systems 7
• 2. Experimental Section 9
• 2.1 MEC Configuration and Operation 9
• 2.2 EIS Analysis for Optimal Voltage Identification 10
• 2.3 MFC Configuration and Operation 11
• 2.4 MFC-MEC System Design: Direct and Battery-Assisted Modes 12
• 2.5 Electrochemical Performance 14
• 2.6 Hydrogen Production Rate Measurement 15
• 3. Result and discussion 16
• 3.1 Hydrogen Production Characteristics According to MEC Applied Voltage 16
• 3.2 Analysis of Electrode and Membrane Potential Behavior with MEC Applied Voltage Changes 19
• 3.3 EIS-Based Internal Resistance Decomposition Analysis and Correlation with Hydrogen Productivity 22
• 3.4 Electrochemical Performance Evaluation of Single Cell and Parallel-Connected Microbial Fuel Cells 26
• 3.5 Direct-Connected MFC-Powered MEC Hydrogen Production 29
• 3.6 Battery-Charged MFC-Powered MEC Hydrogen Production 31
• 4. Conclusions 35
• 5. References 37