Abstract
The efficient and fast recharging of Li-ion batteries without compromising capacity or safety is paramount in advancing energy storage technologies. This study addresses this challenge by developing a novel electrode design known as dual-layer electrode (DLE) technology, achieved via a carefully orchestrated sequential coating process involving two distinct anode materials. The primary objective is to minimize cell polarization, a critical factor impacting charging efficiency and battery longevity, particularly at higher charging currents.The research employs advanced electrochemical techniques such as electrochemical impedance spectroscopy (EIS) and distribution of relaxation times (DRT) analysis to delve into the dynamic evolution of electrode impedances. Notably, synthetic graphite (SG) exhibits varying impedance characteristics with changes in the state of charge (SOC), contrasting with the relatively stable impedance observed in natural graphite (NG) across SOC variations. This fundamental difference is a critical determinant in arranging NG and SG layers within the DLE, strategically considering the temporal SOC gradient encountered during fast charging cycles.The study leverages simulation models alongside experimental validation to ascertain the optimal positioning of NG and SG layers within the DLE structure. The results demonstrate that placing NG atop SG in the DLE configuration significantly reduces overall resistance, leading to remarkable performance gains. Specifically, the DLE exhibits a remarkable 61.0% capacity retention over 200 cycles when charged at a 4 C rate (equivalent to a 15-minute charging duration). This performance surpasses counterparts with reversed sequential coating and even outperforms single-layer electrodes utilizing either NG or NG/SG mixed electrodes.Furthermore, this research contributes valuable insights into the combinatorial sequence for multi-layer coating of various active materials, particularly in thick-electrode designs. The findings hold significant implications for advancing the development of high-performance Li-ion batteries tailored for fast-charging applications across diverse sectors by achieving lower resistivity and enhanced charging efficiency.
Published Version
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