Theoretical Derivation of the Effect of Bonding Current on the Bonding Interface during Anodic Bonding of PEG-Based Encapsulation Materials and Aluminum

This study analyzed the mechanism underlying the effect of the bonding current on the bonding interface during anodic bonding on the basis of the anodic bonding of PEG (polyethylene glycol)-based encapsulation materials and Al. By establishing an equivalent electrical model, the effects of various electrical parameters on the dynamic performance of the bonding current were evaluated, and the change law of the bonding current transfer function was analyzed. By examining the gap deformation model, the conditions for contact between the interface gaps and the bonding current pair were determined, and the influence law of the gap deformation of the bonding interface was derived. By assessing the effect of the bonding current on the ionic behavior, we found that the larger the bonding current, the greater the number of activated mobile ions in the bonding material and the higher the field strength in the cation depletion area. From the anodic bonding experiments, it was found that increasing the bonding voltage can increase the peak current and improve the bonding efficiency. The SEM image after bonding shows that the bonding interface had no obvious defects; the higher bonding voltage can result in a thicker bonding layer.

High ion conductivity based on a polyurethane composite solid electrolyte for all-solid-state lithium batteries

Solid polymer electrolytes (SPE) are considered a key material in all-solid Li-ion batteries (SLIBs). However, the poor ion conductivity at room temperature limits its practical applications. In this work, a new composite polymer solid electrolyte based on polyurethane (PU)/LiTFSI–Al₂O₃–LiOH materials is proposed. By adding a few inert fillers (Al₂O₃) and active agents (LiOH) into the PU/LiTFSI system, the ion conductivity of the SPE reaches 2 × 10⁻³ S cm⁻¹ at room temperature. Exploiting LiFePO₄ (LFP)‖Li as electrodes, the PU-based composite lithium battery is prepared. The experimental result shows that the LFP|SPE|Li displays high specific discharge capacity. The first specific discharge capacities at 0.2C, 0.5C, 1C and 3C are 159.6, 126, 110 and 90.1 mA h g⁻¹ respectively, and the Coulomb efficiency is found to be stable in the region of 92–99% which also shows a desirable cyclic stability after 150 cycles.

Adding inert filler to reduce the coupling effect of functional groups to Li⁺ and modifying the functional groups to reduce the adsorption of Li⁺ can lead to high ionic conductivity.