High energy density hybrid supercapacitor based on 3D mesoporous cuboidal Mn2O3 and MOF-derived porous carbon polyhedrons

Nowadays, it is highly desired to design and fabricate efficient and cost-effective electrode materials for energy conversion and storage devices. Manganese oxides are remarkable electrode material for pseudocapacitors due to their ideal capacitive behaviour, low cost and environmental friendliness. However, low conductivity and poor cycling stability remain major challenges for their commercialization. Herein, we demonstrate the direct growth of mesoporous cuboidal Mn2O3 via a one-step hydrothermal approach on the highly conductive surface of nickel foam (Mn2O3@NF) as a high-performance binder-free electrode material for supercapacitors(SCs). The as-prepared cuboidal Mn2O3 possesses high specific surface area and mesoporous feature which lead to larger number of active sites and improve the electrochemical storage activity. As a result, excellent pseudocapacitive performance is achieved with remarkably enhanced capacitance of 791 Fg-1 at 5 mVs-1 and good cycling stability is observed with retaining 92.5% of its initial capacitance after 5000 continuous charging-discharging cycles. Furthermore, a hybrid SC has been fabricated using Mn2O3@NF as a positive electrode and metal-organic framework (MOF) derived mesoporous carbon as a negative electrode. The hybrid Mn2O3@NF//MC device can operate with a large working potential window of 0.0-1.6 V, which leads to a specific energy density of 112.82 Wh kg−1 at a moderate power density of 320 W kg−1 and also exhibits excellent cycling capability with retaining 86.73% of the original capacitance after 5000 cycles, which is comparable than most of previously reported manganese oxide based SCs. The experimental results show that the Mn2O3@NF can offer great potential for practical energy storage applications.