1. Center for Environmental Science, College of Natural and Computational Sciences, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia
2. Department of Energy Storage, Technical University of Denmark, Anker Engelunds Vej, Building 301, 2800 Kgs Lyngby, Denmark
3. Materials Science Program/Department of Chemistry, College of Natural and Computational Sciences, Addis Ababa University, P.O. Box 33658, Addis Ababa, Ethiopia