Unveiling the electrochemical degradation behavior of 18650 lithium-ion batteries involved different humidity conditions

As an ideal energy storage system, lithium-ion batteries play a vital role in the energy sector. However, aging and degradation are inevitable during the operational life cycle of lithium-ion batteries, especially under unfavorable environmental conditions, which poses a significant challenge to battery performance and longevity. Despite the widespread use of lithium-ion batteries, research on the effects of humidity factors on battery aging is limited. This study is designed to experimentally explore the electrochemical performance and aging mechanisms of batteries in diverse humidity conditions. The study delineates that in general humidity environments, the capacity decay of batteries is notably accelerated. Under saline humidity conditions, this further accelerates the deterioration on battery performance. Electrochemical assessments across different humidity regimes identify a pronounced decline and notable deviation in the peaks of incremental capacity. Concurrently, a significant surge in impedance is observed. These results underscore that harsh humidity conditions expedite the aging process in lithium-ion batteries, with loss of lithium inventory emerging as the primary aging mechanism in such environments. This study reveals how harsh humidity factors accelerate battery aging and has important implications for battery aging mechanisms, safe battery design, and the prediction of battery life under such conditions.