Electrochemical noise investigation of lithium based batteries
With the widespread use of portable technological devices such as smart phones, laptops, tablets and smart watches, and electric cars in recent years, the need for energy is also increasing. Batteries based on lithium chemistry are the primary choice of the portable technology industry due to their small size, light weight, rechargeability and high energy density, and therefore, the interest in lithium-based batteries has been an important academic research topic.
Electrochemical noise measurements are commonly used measurement methods in the corrosion research. In recent years, electrochemical noise measurements have been employed as a non-destructive testing method, especially in lithium-based batteries, but the measurement methods and analyses methods presented in the literature are insufficient. In this thesis, electrochemical noise measurement methods and common analyses methods in lithium-based batteries are summarized, a new approach how to make accurate noise measurement and analysis, and under which conditions lithium-based batteries show noise increase is introduced. The use of lithium alloy as the anode material in rechargeable batteries causes its energy density to be less than the energy density provided by pure metallic lithium used in non-rechargeable batteries. For this reason, the use of pure metallic lithium in rechargeable batteries is extremely important for industrial development. The examination of pure metallic lithium batteries with electrochemical noise, which is a non-destructive measurement method during charging and discharging, and imaging with optical microscope in situ and after death with spectroscopic analysis methods are presented.