A facile and functional process to enhance electrochemical performance of silicon anode in lithium ion batteries

Abstract

Silicon is a promising anode active material for lithium ion batteries due to improvements to overcome the volume expansion problem and preserve the electrode structural integrity during the lithiation and delithiation processes. Significant studies have been performed to overcome this problem and make silicon available for commercial applications. In this study, we developed a facile and functional method to demonstrate the possibility of widespread usage of silicon anode. Here, two methods were investigated; neutralization of poly(acrylic) acid (PAA) and calendering process during electrode production. PAA without neutralization is commonly used in silicon based anodes. Calendering is a typical process for cathode preparation. However, it is not generally utilized for making silicon anodes. This study aims to show the effect of PAA neutralization and anode calendering on the electrochemical performance of cells in comparison to anodes prepared by conventional processes. Furthermore, a high mass loading is a critical step for the use of Si anode commercially. The electrode was successfully loaded in this study as 1 mg/cm2. Electrochemical performance measurements showed that 1370mAh/g specific capacity was achieved after neutralization of PAA and calendering of the electrode at the 100th cycle. Meanwhile, the calendered electrode prepared with PAA polymer showed a specific capacity of 511 mAh/g after 100 cycles. Traditionally, graphite is used as anode material in commercial batteries and theoretical specific capacity is 372mAh/g. Our observations with quite high specific capacity achieved by the process applied in this study show an important promise for the use of silicon based anode materials in the future utilization of Li ion batteries.