Dongliang Yan

Biomorphic Synthesis of Mesoporous Co3O4 Microtubules and Their Pseudocapacitive Performance

A novel meosoporous tubular Co3O4 has been fabricated by a simple and cost-effective biomorphic synthesis route, which consists of infiltration of cotton fiber with cobalt nitrate solution and postcalcination at 673 K for 1 h. Its electrochemical performance as a supercapacitor electrode material is investigated by means of cyclic voltammetry and chronopotentiometry tests. Compared with bulk Co3O4 prepared without using cotton template, biomorphic Co3O4 displays 2.8 fold enhancement of pseudocapacitive performance because of the unique tubular morphology, relative high specific surface area (3 and 0.8 m(2)/g for biomorphic Co3O4 and bulk Co3O4, respectively), and mesoporous nature.

Supercapacitive properties of Mn3O4 nanoparticles bio-synthesized from banana peel extract

A green approach to the synthesis of Mn3O4 nanoparticles using banana peel extract as both reducing and capping agent has been described. The as-obtained Mn3O4 electrode exhibits acceptable electrochemical performance (216 F g−1 at 0.3 A g−1, 93% capacity retention after 2000 cycles).

Mesoporous ZnMn2O4 Microtubules Derived from a Biomorphic Strategy for High-Performance Lithium/Sodium Ion Batteries

ZnMn2O4 microtubules (ZMO-MTs) with a mesoporous structure are fabricated by a novel yet effective biomorphic approach employing cotton fiber as a biotemplate. The fabricated ZMO-MT has approximately an inner diameter of 8.5 μm and wall thickness of 1.5 μm. Further, the sample of ZMO-MT displays a large specific surface area of 48.5 m2 g-1. When evaluated as a negative material for Li-ion batteries, ZMO-MT demonstrates an improved cyclic performance with discharge capacities of 750.4 and 535.2 mA h g-1 after 300 cycles, under current densities of 200 and 500 mA g-1, respectively. Meanwhile, ZMO-MT exhibits superior rate performances with high reversible discharge capacities of 614.7 and 465.2 mA h g-1 under high rates of 1000 and 2000 mA g-1, respectively. In sodium ion batteries applications, ZMO-MT delivers excellent high discharge capacities of 102 and 71.4 mA h g-1 after 300 cycles under 100 and 200 mA g-1, respectively. An excellent rate capability of 58.2 mA h g-1 under the current density of 2000 mA g-1 can also be achieved. The promising cycling performance and rate capability could be benefited from the unique one-dimensional mesoporous microtubular architecture of ZMO-MT, which offers a large electrolyte/electrode accessible contact area and short diffusion distance for both of ions and electrons, buffering the volume variation originated from the repeated ion intercalation/deintercalation processes.