| Popis: |
In the commercial industry, lithium-ion batteries (LIB) with a high energy density have already received more attention. The need for high-energy LIB for electric vehicles (60-70 kWh to travel 300 miles) has prompted research into next-generation battery materials. As an anode material, composite Si has been shown to have better cycle stability than bare Si. However, the initial capacity loss (ICL) of Si anode is high due to the formation of surface film compounds on the anode surface during the first discharge process, and it is irreversible in nature. Direct contact prelithiation (PL) is a simple, practical, and scalable technique for overcoming first cycle loss and large volume expansion difficulties in silicon anode (with 30 wt percent Si loading) material, but no comprehensive research has been done on it. The effect of externally applied pressure (weight), microstructure, and operating temperature have all been investigated in order to gain a better knowledge of direct contact PL as a function of PL time. Electrochemical techniques and other microstructural analyses were used to investigate the impact of PL on Si-C electrode surfaces. The thickness of the SEI layer increases as the PL time increases and diminishes after 2 minutes. With a 20 g externally applied weight, the appropriate PL time was found to be between 15 (PL-15) and 30 (PL-30) minutes, with 83.5 % and 97.3 % initial Coulombic efficiency (ICE), respectively. The PL-15 and PL-30 cells had higher cyclic stability than the PL-0 (without prelithiation), retaining more than 90% of capacity retention after 500 cycles at a current density of 1 A g-1. The highest discharge capacity was reported for PL-15 and PL-30 at 45°C operating temperature with limited cyclability. To obtain superior cell performance, we propose a synchronized method in prelithiation time, pressure, and temperature. Figure 1 |
