Abstract: The polymer solid electrolyte has a simple preparation method, good film-forming performance, and good electrode-electrolyte interface contact. However, the low room temperature ionic conductivity, poor electrochemical stability, and the inability to match the cathode material with a wide voltage window limit the large-scale commercial application of polymer solid electrolytes; graphene has excellent mechanical, mechanical properties, photoelectric thermal properties and a large specific surface area, high ion conductivity and electron migration number, so it has strong electrical conductivity. In this paper, a typical polymer solid electrolyte polyethylene oxide (PEO) and graphene composite are selected to further enhance the electrochemical performance of the composite material. Experiments have found that the polymer/graphene composite solid electrolyte membrane with graphene added does not decompose significantly before 5 V, which clarifies that it has good electrochemical stability. And the first charge-discharge specific capacity of the composite solid electrolyte membrane is higher than that of the single polymer solid electrolyte membrane. Neither the diffraction peak nor the reduction peak shifted after 5 cycles, and the cycle life was still 99.449% after 100 cycles, indicating that it has good cycle stability. Therefore, the application of polymer/graphene composite solid electrolyte membranes in all-solid-state lithium batteries is feasible.
Abstract: Due to the advantages in weather resistance, light transmittance and dimension stability, PMMA has been widely used in various fields such as aerospace and optical engineering. However, fully automatic robot systems are seldom used for polishing complex PMMA parts with high surface integrity. Therefore, a robotic polishing system with a new active end-effector is developed in this paper. In the system, a 6-degree-of-freedom industrial robot is utilized to polish the part profile along the preprogrammed paths, and then the system configuration is introduced in detail. For precisely controlling the normal contact force, both a linear voice coil motor and a force sensor are used in the designed end-effector. Meanwhile, a tilt sensor is also used to compensate the gravity component of the polishing tool along the force-controlled direction. Subsequently, a hybrid force controller, which consists of a PID controller and a Fuzzy controller, is designed to maintain the contact force between the polishing tool and the part within an allowable range. Finally, validation experiments are conducted with the designed robotic polishing system on a complex PMMA part. The experimental results show that the proposed robotic polishing system can strictly control the normal contact force and ensure high surface integrity of the PMMA part.