Lifetime Optimization of Amorphous Silicon Thin-Film Anodes for Lithium-Ion Batteries

Abstract

Silicon has emerged as a highly promising anode material for lithium-ion batteries (LIBs) owing to its high specific capacity and low voltage. However, previous research on silicon-based anodes has not adequately addressed inherent issues, leading to limited commercial applications on a large scale. Therefore, further scientific investigation is necessary to uncover the lithiation/delithiation process in silicon materials and understand the influence of electrode potential and charge state on the kinetic process during charge and discharge. This understanding will be instrumental in gradually enhancing the performance of silicon materials. Herein, amorphous silicon films were prepared for LIB anodes using the magnetron sputtering method. Molecular dynamics simulations were conducted to investigate the microstructure and volumetric changes of the sputtered amorphous silicon anode during the lithiation and delithiation processes. Additionally, electrochemical characterization techniques such as a galvanostatic intermittent titration technique, electrochemical impedance spectroscopy, and galvanostatic charge–discharge test were employed to explore the electrochemical properties of silicon electrodes. Electrochemical analysis techniques, such as the differential capacity method and distribution of relaxation times, were also used to investigate the deterioration mechanisms of the electrochemical and conversion properties of amorphous silicon anodes. Results revealed that the lithium-ion content in Li x Si, determined through the set cutoff voltage during charge/discharge cycling, considerably affected the volume change of the silicon anode and the composition and integrity of the solid electrolyte interface after cycling. The optimum discharge cutoff voltage was found to be 0.08 V for the amorphous silicon electrode, leading to an optimum cycle life with a capacity retention of 87.17% after 100 cycles.

Chemical Bonding and Activity of Atomically Dispersed Silicon in Two- and Three-Dimensional Materials

“…Silicon, as the second most abundant element of the earth’s crust, has been attracting great interest from various fields owing to its unique characteristics such as affordability, environmental friendliness, novel electronic properties, and remarkable mechanical stability. − Silicon-based devices have emerged as critical components in diverse applications, including optoelectronics, microelectronics, smart sensors, solar cells, etc. − It is undeniable that the modern technological world owes a great deal to silicon. Nonetheless, with the rapid development of science and information technology, there are growing demands for improving the performance of silicon-based materials, motivating researchers to devote a lot of effort to address this challenge.…”