Confronting Issues of the Practical Implementation of Si Anode in High-Energy Lithium-Ion Batteries

Abstract

Over 20 years, Si has been investigated as a promising alternative to conventional graphite because of its high specific capacity and proper working voltage. As numerous strategies have demonstrated their improved electrochemical properties by addressing the intrinsic challenges of Si anode, the practical investigation with a full cell has been regarded as an important task to verify their feasibilities. In this Perspective, we discuss key issues in the practical implementation of the Si anode in the high-energy full cell. With the target of improvement in the volumetric energy density, the comprehensive overview of an electrochemical cell design for Si anodes is presented with its influence on electrochemical properties. Moreover, we highlight the electrode swelling issues and the capacity fading of the Si anode, which is pronounced in the full cell rather than in the half cell. Finally, we offer insights regarding the potential future directions in the development of the Si anode for high-energy lithium-ion batteries. To satisfy ever-increasing energy demands, improving the energy density of the lithium-ion battery (LIB) has been regarded as one of the most important agendas in the battery field. In the past few decades, silicon (Si) as the high-capacity anode has been intensively explored to substitute the conventional carbonaceous anode. As many efforts have succeeded in understanding the mechanism of the Si anode and in overcoming its intrinsic challenges, feasibility study of its practical implementation in the full cell has been highly desirable in taking a step toward high-energy LIBs. This Perspective systematically addresses the critical issues of Si anodes based on the conventional electrochemical cell design. With the flow chart of the electrochemical cell design, several parameters that affect the electrochemical properties of Si anodes are briefly introduced. In addition, the dependence of volumetric energy density on electrode swelling is highlighted, and the difference in capacity fading mechanisms between the half cell and the full cell is discussed in terms of the electrochemical cell. Overall, this Perspective gives an insight into the potential future direction for the development of the Si anode and the evaluation of new Si anodes to ensure the enhancement of volumetric energy density and cycle life in the full cell. While the silicon anode has been vigorously studied for the high-energy lithium-ion battery (LIB), the practical application of the silicon anode still seems tardy. To stimulate the implementation of Si anodes in high-energy LIB, we discuss practical issues of Si anodes with the conventional electrochemical cell design. This Perspective reminds the reader about the major aim of developing the Si anode, i.e., improving the volumetric energy density, and what should be considered for its practical application.