Paper-Based Zn-Ag₂O Batteries Self-Driven CNT-PDMS Strain Sensors For Joint Motion Monitoring

Wearable electronics have numerous advantages such as lightweight,flexible and portable,and have received wide attention in medical testing,medical rehabilitation,environmental monitoring and other fields.However,the development of wearable electronics has also put forward higher requirements for flexible energy storage devices and flexible sensors at the same time.It is of great theoretical and practical value to develop flexible rechargeable batteries and flexible strain sensors with high performance,low cost and easy integration.In this thesis,a flexible quasi-solid-state Zn-Ag₂O battery based on filter paper（FP）and a flexible CNT-PDMS strain sensor were realized respectively,and a solar energy-based self-driven joint motion monitoring system prototype was further developed.The main contents are as follows:1.A highly conductive Au and Ni modified filter paper（CFP）was realized via in-situ metal growth and electroless nickel immersion gold technology.During the experiment,the soaking time of nickel sulfate,sodium borohydride and commercial gold plating solution were set as independent variables,and the sheet resistance of CFP was set as the dependent variable.The optimized process conditions were obtained by the orthogonal test.The optimized CFP allows for the unification of good electrical conductivity and high mechanical flexibility.2.Flexible quasi-solid-state Zn-Ag₂O batteries were realized using the optimized CFP as the current collector.Flexible Ag₂O/CFP cathodes were realized via electroless plating and electrochemical oxidation.Flexible Zn/G/CFP anodes were realized via electrochemical deposition.The electrode structures of Ag₂O nanoparticles and Zn metal particles rooted on the CFP were obtained.In particular,the large surface areas and root networks of the stacked Ag₂O nanoparticles provided abundant electrochemically active sites and ion diffusion channels for enhanced capacity properties.The unique tree-root-like electrode structure created robust interlocking interfaces and effectively improved the interfacial adhesion of active materials/substrates.The assembled quasi-solid-state Zn-Ag₂O batteries achieved an areal specific capacity of 1.08 m Ah cm^-2 and a capacity retention of 77.3%even after100cycles.Moreover,the batteries presented good mechanical stability under various flexural deformations,including bending,folding,and twisting,and exhibited minimal capacity changes after 1000 bending cycles.3.Flexible skin-like CNT-PDMS flexible strain sensors were realized via ultrasonic dispersion and liquid-phase mixing.According to the percolation theory,it is determined that the percolation threshold is between 2～4 wt%.At a CNT content of 4wt%,the CNT-PDMS strain sensors delivered the highest sensitivity（GF=67.08 atε=50%）,a large stretchable range（ε>90%）,high repeatability and cycling durability.The results of finger motion monitoring show that the resistance variation of the CNT-PDMS strain sensor can dynamically match the finger bending.A solar energy-based self-driven joint motion monitoring system prototype based on the CNT-PDMS strain sensor was developed in combination with the flexible quasi-solid-state Zn-Ag₂O battery and a solar cell.The self-driven system can real time monitor the strain signal generated by human joint motion on the We Chat applet without external power supply.