1. Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
2. Energy and Environment Directorate, Pacific Northwest National Laboratory (PNNL), 902 Battelle Boulevard, Richland, Washington 99354, United States
3. Intelligent Sensors Research Section, Electronics and Telecommunications Research Institute (ETRI), Daejeon 34129, Republic of Korea