Synthesis of Cu-Doped Mn3O4@Mn-Doped CuO Nanostructured Electrode Materials by a Solution Process for High-Performance Electrochemical Pseudocapacitors

Hasi Rani Barai; Nasrin Siraj Lopa; Faiz Ahmed; Nazmul Abedin Khan; Sajid Ali Ansari; Sang Woo Joo; Md Mahbubur Rahman

doi:10.1021/acsomega.0c02740

Synthesis of Cu-Doped Mn₃O₄@Mn-Doped CuO Nanostructured Electrode Materials by a Solution Process for High-Performance Electrochemical Pseudocapacitors

ACS Omega. 2020 Aug 27;5(35):22356-22366. doi: 10.1021/acsomega.0c02740. eCollection 2020 Sep 8.

Authors

Hasi Rani Barai¹, Nasrin Siraj Lopa², Faiz Ahmed², Nazmul Abedin Khan³, Sajid Ali Ansari⁴, Sang Woo Joo¹, Md Mahbubur Rahman²

Affiliations

¹ Department of Mechanical Engineering, Yeungnam University, Gyeongsan 38541, Korea.
² Department of Energy and Materials, Konkuk University, Chungju 27478, Korea.
³ Department of Mathematical and Physical Sciences, East West University, Dhaka 1212, Bangladesh.
⁴ Department of Physics, College of Science, King Faisal University, Al-Ahsa 31982, Saudi Arabia.

Abstract

Cu-doped Mn₃O₄ and Mn-doped CuO (CMO@MCO) mixed oxides with isolated phases together with pristine Mn₃O₄ (MO) and CuO (CO) have been synthesized by a simple solution process for applications in electrochemical supercapacitors. The crystallographic, spectroscopic, and morphological analyses revealed the formation of all of the materials with good crystallinity and purity with the creation of rhombohedral-shaped MO and CMO and a mixture of spherical and rod-shaped CO and MCO nanostructures. The ratio of CMO and MCO in the optimized CMO@MCO was 2:1 with the Cu and Mn dopants percentages of 12 and 15%, respectively. The MO-, CO-, and CMO@MCO-modified carbon cloth (CC) electrodes delivered the specific capacitance (C _s) values of 541.1, 706.7, and 997.2 F/g at 5 mV/s and 413.4, 480.5, and 561.1 F/g at 1.3 A/g, respectively. This enhanced C _s value of CMO@MCO with an energy density and a power density of 78.0 Wh/kg and 650.0 W/kg, respectively, could be attributed to the improvement of electrical conductivity induced by the dopants and the high percentage of oxygen vacancies. This corroborated to a decrease in the optical band gap and charge-transfer resistance (R _ct) of CMO@MCO at the electrode/electrolyte interface compared to those of MO and CO. The net enhancement of the Faradaic contribution induced by the redox reaction of the dopant and improved surface area was also responsible for the better electrochemical performance of CMO@MCO. The CMO@MCO/CC electrode showed high electrochemical stability with a C _s loss of only ca. 4.7%. This research could open up new possibilities for the development of doped mixed oxides for high-performance supercapacitors.