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Magnesium (Mg)-rich primer is considered as a substitute for high polluted chromate treatment technology to provide cathodic protection for aluminum (Al) alloy. In this paper, Mg-rich primer with comprehensive properties was prepared by modifying epoxy resin using direct mixing. Specifically, the influence factors on the dispersion of Mg powder in epoxy, the modification of epoxy resin using organic silicones and the performance of Mg-modified epoxy composite coating were studied. The results show that Mg powder with small particle size has a better dispersion in epoxy; The mechanical property such as flexibility and impact resistance decreases with the addition of Mg powder, but which was improved when using modified epoxy as the resin matrix due to introduction of Si-O-Si flexible chain; In addition, the grafting efficiency between hydroxyl terminated polydimethylsiloxane and epoxy resin was improved because of the introduced silane coupling agent like KH550 contains amino group; The electrochemical test results indicate Mg-rich primer could provide effective electrochemical protection for Al alloy by raising the corrosion potential and reducing the corrosion current density to bare substrate,respectively.

Summary: Poly(ethylene oxide) (PEO) polymer electrolyte has been regarded as a potential solid electrolyte which can be applied in all‐solid‐state lithium‐ion batteries (ASSLIBs). Nevertheless, low electrochemical properties and poor electrolyte/Li anode interfacial stability hinder its further application. In our work, the Li1.3Al0.3Ti1.7(PO4)3 (LATP) nanomaterials with Nasicon structure have been synthesized using a simple solvent‐thermal method, followed by being embedded into PEO polymer to form LATP filled PEO solid composite electrolytes. Effects of LATP content and particle size on electrochemical performances of solid electrolytes have been studied. By adjusting the calcination temperature, the uniformly distributed Nasicon‐type LATP powders with different sizes can be obtained. The electrochemical properties of PEO polymer electrolyte have been effectively enhanced by filling LATP nanoparticles. The composite electrolyte filled with 5 wt% LATP particles calcined at 850°C exhibits a high ionic conductivity of 5.24×10−4 S cm−1 at 55°C, which has a high electrochemical stability window of over 5 V versus Li/Li+ and a superior interfacial stability with Li metal. A LiFePO4/Li ASSLIB fabricated with the optimum composite electrolyte shows the excellent rate capability, and its discharge capacities at 0.2C, 0.5C, 1C, and 2C are 151.97, 151.56, 145.51, and 128.02 mAh·g−1. Moreover, the discharge capacity of the cell decreases from 151.69 to 130.53 mAh·g−1 after 100 charge‐discharge cycles at 0.5C rate, and the corresponding capacity retention is 86.05%. These results demonstrate that LATP nanoparticles obtained via the solvent‐thermal method are the alternative fillers for PEO polymer electrolyte. [ABSTRACT FROM AUTHOR]

The polyethylene oxide (PEO) solid electrolyte is a promising candidate for all solid state lithium-ion batteries (ASSLIBs), but its low ionic conductivity and poor interfacial compatibility against lithium limit the rate and cycling performance of the cell. Herein, the novel and efficient TiO 2 @polydopamine (PDA) fillers have been synthesized by coating PDA onto the surface of the TiO 2 nanofibers, which are then incorporated into PEO matrices to form the composite electrolyte. The composite electrolyte displays a higher ionic conductivity of 4.36 × 10 -4 S cm -1 , a wider electrochemical window up to about 5 V and a higher t Li + of 0.190 at 55 °C compared to the PEO electrolyte. Additionally, the Li/composite electrolyte/Li batteries show a stable Li plating/stripping cycle performance, indicating good interfacial compatibility between the composite electrolyte and lithium. Thus, the LiFePO 4 /Li ASSLIBs display a fantastic rate performance and cycling stability, and deliver superior discharge specific capacities of 153.83 and 136.45 mA h g -1 at current densities of 0.5C and 2C, achieving good capacity retentions of 93.27% and 91.23% at 0.5C and 1C after 150 cycles, respectively. Therefore, the PEO-TiO 2 @PDA composite electrolyte is a potential solid electrolyte for ASSLIBs.