Construction and ultrasonic inspection of the high-capacity Li-ion battery based on the MnO₂ decorated by Au nanoparticles anode

Lithium (Li)-ion batteries have become one of the main energy sources for electric vehicles and energy storage systems, which puts forward higher requirements for the detection of battery state of health (SOH). The SOH of batteries is crucial for areas such as battery management and renewable energy storage. Accurately evaluating the SOH of batteries can optimize charging and discharging strategies and extend battery life. Therefore, accurately and effectively monitoring the SOH of Li batteries is of great significance. An ultrasonic testing technology has been proposed that can non-destructively test the Li battery SOH, enabling accurate judgment of batteries in poor or damaged conditions. Firstly, the hetero-structured MnO2-Au has been constructed as the anode for Li-ion batteries. MnO2-Au heterojunction enhances electronic conductivity and ion conductivity. The MnO2-Au has exhibited high specific capacity and superior rate performances, which can well satisfy the ultrasonic inspection of the battery. Then, the ultrasonic testing has been conducted on batteries with different ages. The results suggest that batteries with short circuits have the highest nonlinear coefficient, while batteries with short circuits after long cycles have the lowest nonlinear coefficient. The nonlinear coefficient of batteries with different charging and discharging states is in the middle.