Highly Effective Self-Propagating Synthesis of Lamellar ZnO-Decorated MnO2 Nanocrystals with Improved Supercapacitive Performance

A series of MOx (M = Co, Ni, Zn, Ce)-modified lamellar MnO2 electrode materials were controllably synthesized with a superfast self-propagating technology and their electrochemical practicability was evaluated using a three-electrode system. The results demonstrated that the specific capacitance varied with the heteroatom type as well as the doping level. The low ZnO doping level was more beneficial for improving electrical conductivity and structural stability, and Mn10Zn hybrid nanocrystals exhibited a high specific capacitance of 175.3 F·g−1 and capacitance retention of 96.9% after 2000 cycles at constant current of 0.2 A·g−1. Moreover, XRD, SEM, and XPS characterizations confirmed that a small part of the heteroatoms entered the framework to cause lattice distortion of MnO2, while the rest dispersed uniformly on the surface of the carrier to form an interfacial collaborative effect. All of them induced enhanced electrical conductivity and electrochemical properties. Thus, the current work provides an ultrafast route for development of high-performance pseudocapacitive energy storage nanomaterials.

First Principles Research on the Magnetic Properties of Na and Cl doped ZnO

ZnO is considered as a wide bandgap material because it has a 3.4 eV direct bandgap. This wide bandgap characteristic causes good transparency, high electron mobility and luminescence at room temperature.The unique and tuneable properties of nanostructured ZnO shows excellent stability in chemically as well as thermally stable n-type semiconducting material with wide applications such as in luminescent material, supercapacitors, battery and solar cells. To be applied to a variety of needs, price control bandgap is needed. Likewise, control over the magnetic nature. Therefore we need a study related to bandgap modification, one of them is by giving impurity atoms. Atom Na and Cl were chosen as representatives of donors and acceptors. Atomistic calculations use the Functional Density Theory method which is implemented in ABINIT software. Relaxation and convergence research results are used to find the most stable energy value of ZnO.. The results showed Magnetic Properties in ZnO doping Na obtained magnetization values of 1.4802 𝜇𝐵 greater than pure ZnO that is 0.9394 𝜇𝐵 while ZnO doping Cl obtained magnetization values of 0.8593 𝜇𝐵 smaller than pure ZnO. In conclusion the ZnO doping magnetic properties of Na increase magnetization and Cl doping also change the magnetic properties by decreasing ZnO magnetization.