Suktha Phansiri, Chiochan Poramane, Krittayavathananon Atiweena, Sarawutanukul Sangchai, Sethuraman Sathyamoorthi, Sawangphruk Montree
Department of Chemical and Biomolecular Engineering, School of Energy Science and Engineering, Vidyasirimedhi Institute of Science and Technology Rayong 21210 Thailand
Centre of Excellence for Energy Storage Technology (CEST), Vidyasirimedhi Institute of Science and Technology Rayong 21210 Thailand.
RSC Adv. 2019 Sep 10;9(49):28569-28575. doi: 10.1039/c9ra05444h. eCollection 2019 Sep 9.
Manganese oxide nanoparticles decorated on 3D reduced graphene oxide aerogels (3D MnO /rGO) for neutral electrochemical capacitors were successfully produced by a rapid microwave reduction process within 20 s. The symmetric electrochemical capacitor of 3D MnO /rGO (Mn 3.0 at%) storing charges both electric double layer capacitance (EDLC) and pseudocapacitance mechanisms exhibits a specific capacitance of 240 F g as compared with 190 F g of that using the bare 3D rGO at 0.5 A g in 1 M NaSO (aq.) electrolyte. It retains 90% of the initial capacitance after 10 000 cycles, demonstrating high cycling stability. In addition, the charge storage mechanism of 3D MnO /rGO was investigated using an electrochemical quartz crystal microbalance. gas analysis using differential electrochemical mass spectrometry (DEMS) shows the CO evolution at a cell potential over 1 V indicating that the positive electrode is possibly the voltage limiting electrode in the full cell. This finding may be useful for further development of practical high power and energy supercapacitors.
通过快速微波还原工艺在20秒内成功制备了负载在三维还原氧化石墨烯气凝胶（3D MnO₂/rGO）上的氧化锰纳米颗粒用于中性电化学电容器。3D MnO₂/rGO（Mn含量为3.0原子%）的对称电化学电容器同时通过双电层电容（EDLC）和赝电容机制存储电荷，在1 M Na₂SO₄（水溶液）电解质中，在0.5 A/g的电流密度下，其比电容为240 F/g，而使用裸3D rGO时的比电容为190 F/g。在10000次循环后，它保留了初始电容的90%，显示出高循环稳定性。此外，使用电化学石英晶体微天平研究了3D MnO₂/rGO的电荷存储机制。使用差分电化学质谱（DEMS）进行的气体分析表明，在电池电位超过1 V时会有CO释放，这表明正极可能是全电池中的电压限制电极。这一发现可能对实际高功率和能量超级电容器的进一步发展有用。
