Institutional Repository of Institute of Process Engineering, CAS (IPE-IR）
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Multifunctional polyzwitterion ionic liquid coating for long-lifespan and dendrite-free Zn metal anodes
No full textAqueous zinc (Zn) metal batteries have received widespread attention due to their high safety and environmental friendliness. However, the uncontrollable growth of dendrites, hydrogen evolution reaction, and corrosion severely limit the practical application of aqueous Zn batteries. Herein, a multifunctional water-blocking polyzwitterion ionic liquid coating poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)-co-tert-butyl acrylate) as the protective layer of the Zn metal anode is proposed to solve these issues. The water-blocking tert-butyl acrylate can prevent water molecules from contacting the Zn metal anode, which plays a key role in inhibiting the hydrogen evolution reaction and corrosion. Meanwhile, zwitterionic ionic liquid moieties are able to tune the solvation environment of the Zn2+ at the electrode/electrolyte interface, inducing compact and planar deposition of the Zn metal. With this synergy effect, the assembled Zn//Zn and Zn//Cu cells achieve a long-term stable plating/stripping performance over 2500 h and a high average coulombic efficiency of 98.6% for 1500 cycles. The Zn//MnO2 and Zn//Mg0.1V2O5 center dot H2O full cells show negligible capacity decay (0.005%) after 4500 cycles. This work provides a new opportunity to protect Zn anodes by water-blocking polyzwitterion ionic liquid coatings in the aqueous electrolyte
Preparation of aromatic polyamide with ultra-high intrinsic breakdown strength via layered stacking structure induced by coplanar monomer
No full textDielectric polymers with high breakdown strength (Eb) and high retention rate of breakdown strength at elevated temperature have important application potential in advanced electrical insulation devices. Herein, the aromatic heterocyclic diamine monomer, 5-amino-2-(2-hydroxy-4-aminobenzene)-benzoxazole (HBOA), was synthesized. Theoretical calculation and single crystal date demonstrated fully the formation of intramolecular H-bond of OH?N]C between benzoxazole and benzene ring in HBOA, which endows the monomer a coplanar geometry. Moreover, the aromatic polyamide films were prepared by polycondensation of HBOA, and the in -plane orientation of films increases with increasing the coplanar HBOA content, which reduces the orientation confusion and cavity of chains packing. When the HBOA content is over 70%, the films exhibit dense-layered stacking structure with high crystallinity. It is found that the dense-layered stacking structure can prevent the films breakdown and failure effectively, which endows the homopolymerization (HBOA-100) film with Eb of 771 kV/mm. Moreover, the Eb of the HBOA-100 film is still as high as 634 kV/mm at 150 ?C, and its retention rate of Eb reaches 82% in high temperature environment. In addition, tensile strength of the HBOA-100 film is nearly 343 MPa, glass transition temperature is about 334 ?C and the thermal stability up to 487 ?C
Tuning interfacial ion distribution to improve energy density of supercapacitors
No full textSupercapacitors as energy carriers have the advantages of high-power efficiency and long-term stability. An improvement of their energy density promises a solution to make up for the weakness of secondary batteries at a high rate of applications. Here we report an attempt to improve the energy density of supercapacitor by tuning ions arrangement at the electrode-electrolyte interface. Upon the theoretical analysis with classical density functional theory (CDFT), we find that the capacitance of the supercapacitor is maximized at a mediate con-centration of electrolytes, i.e., 1.0 M, where ions accumulate near the electrode surface and display a few multilayered oscillatory distributions. Further, by adjusting the dielectric constant of electrolyte solution and the electrode surface voltage, the interfacial ion distribution is tuned to optimize the energy density of super -capacitors. The theoretical results are corroborated by designed experiments, confirming the role of interfacial ion distribution in specific capacitance. This study shows that an appropriate interfacial ion distribution is beneficial to obtaining high capacitance, highlighting an unusual solution to improve the energy density of supercapacitors
Effect of K2O on the crystallization mechanism of SiO2-Li2O glass analyzed by molecular dynamic simulation
No full textThe molecular dynamics method is used to analyze the effect of K2O on crystallization of SiO2-Li2O glass. The dependence of Q(n) (Number of bridging oxygens connected to a silicon atom in the network) on temperature was calculated, which was used to analyze the crystallization behavior of three glasses combined with their XRD results. The relationship between Q(n) and crystalline phases was finally established. When Q(3) > Q(2) and Q(4) is high, LD is the only crystalline phase at both low and high temperature (with a cutoff point of 973 K). When Q(3) > Q(2) and Q(4) is low, LMS is a major crystalline phase and LD is a minor crystalline phase at low temperature, but LD is a major crystalline phase and LMS is a minor crystalline phase at high temperature. When Q(3) approximate to Q(2) and Q(4) is low, LMS is the only crystalline phase at both low and high temperature
