Search

As a typical spinel structure material, ZnMn2O4 has been widely researched in the field of electrode materials. However, ZnMn2O4 nanoparticles as electrode materials for supercapacitors have the disadvantages of low conductivity, inferior structural integrity, and easy aggregation, resulting in unsatisfying electrochemical performance. In this work, we use a hydrothermal method and high-temperature calcination to deposit ZnMn2O4 nanoparticles on carbon cloth and explore the influence of hydrothermal reaction time on the deposition morphology and distribution of ZnMn2O4 nanoparticles on carbon cloth. The deposition process of ZnMn2O4 nanoparticles on carbon cloth was analyzed, and a ZMO-9 electrode was deduced to be the most suitable electrode for supercapacitors. A series of electrochemical performance tests show that the ZMO-9 electrode has excellent specific capacitance (specific capacity) (499 F·g−1 (299.4 C·g−1) at a current density of 1 A·g−1) and rate performance (75% capacitance retention at a current density of 12 A·g−1). The assembled asymmetric supercapacitor has an energy density of 46.6 Wh·kg−1 when the power density is 800.1 W·kg−1. This work provides a reference for the structural design of ZnMn2O4 supercapacitor electrode materials and the improvement of electrochemical properties. [ABSTRACT FROM AUTHOR]

The present paper reported a novel bipolar-pulse cathodic plasma electrolytic deposition (BP-CPED) technique with a low current density. This newly developed CPED technique can break down the barriers of the existing CPED technique with higher current density. In this report, ceramic coatings were successfully prepared on aluminum alloy via the BP-CPED technique in an aqueous carbamide-based electrolyte. Data recording results in the reacting process show that there is the current density of the cathode below 0.15 A/cm2 and that of the anode below 0.035 A/cm2, which approximately reaches the level of conventional MAO technique. Interestingly, the addition of PEG into the electrolyte can further reduce the current density and effectively improve the coating quality. The kinetic of the BP-CPED process was discussed based on the evolution of current density/voltage-time curves and spark discharge phenomena. SEM observations illustrate that BP-CPED coatings possess a typical porous-surface feature. XRD analysis indicates that the coating was mainly composed of Al2O3 and Al4C3. Al2O3/Al4C3/ZrO2 composite coatings fabricated after Zr-doping reflected the successful Zr-incorporation into the coating, which demonstrated that the BP-CPED technique can be used to design the coating composition by the doping modification. The direct pull-off and thermal shock tests confirmed that new BP-CPED coatings obtained under the cathodic plasma discharge have excellent bonding strength. It is possible that this novel BP-CPED technique can provide a promising choice in developing the large-area CPED surface treatment for the industrial application. [ABSTRACT FROM AUTHOR]

Hierarchical CoFeO/NiFeO nanocomposites are prepared via a facile hydrothermal method, in which CoFeO nanoparticles are coated by NiFeO nanoparticles to form a novel nanostructure. Comparing with the single component of either CoFeO electrodes or NiFeO electrodes, the as-prepared hierarchical CoFeO/NiFeO nanocomposites electrodes deliver a higher specific capacitance of 269 F g at a current density of 1 A g and exhibit capacity retention of 81% after 10000 charge-discharge cycles. The improved electrochemical performance demonstrates that hierarchical CoFeO/NiFeO nanocomposites are promising materials and provide a new idea for future generation supercapacitors. [ABSTRACT FROM AUTHOR]

[Display omitted] This study aims to prepare an organic-inorganic reticular polymer electrolyte. Isocyanate acts as a bridge that connects fumed silica and PEO molecular chains. The PEO-TDI-SiO 2 solid polymer electrolytes developed can significantly have improved ionic conductivity of 0.12 mS cm−1 at ambient temperature. This is because the TDI-SiO 2 nanoparticles inhibits polymer crystallization which provides more continuous Li-ion transport pathways. Tests at 60 °C indicate that the cross-linked structure of covalent TSI bonded to PEO effectively enlarges the electrochemical window of the polymer electrolyte to 5.6 V. Also, the PTSI electrolyte membrane has a higher Li+ transference number of 0.33 compared to the PEO-LiTFSI electrolytes. It is worth noting that the assembled LiFePO 4 |PTSI8%|Li cells deliver outstanding rate performance and stable cycling performance. All these considerable merits of PTSI membrane demonstrate that PTSI is a promising candidate that can be used as solid polymer electrolytes for the next-generation Li-ion batteries. [ABSTRACT FROM AUTHOR]