Thermally Crosslinked Polyimide Binders for Si-alloy Anodes in Li-ion Batteries

Abstract

Silicon (Si) has attracted considerable attention due to its high theoretical capacity compared to conventional graphite anode materials. However, Si-based anode materials suffer from rapid capacity loss due to mechanical failure caused by large volume change during cycling. To alleviate this phenomenon, crosslinked polymeric binders with strong interactions are highly desirable to ensure the electrode integrity. In this study, thermally crosslinked polyimide binders were used for Si-alloy anodes in Li-ion batteries. The crosslinked polyimide binder was found to have high adhesion strength, resulting in enhanced electrode integrity during cycling. Therefore, the Si-alloy anodes with crosslinked polyimide binder provide enhanced electrochemical performance, such as Coulombic efficiency, capacity retention, and cycle stability.

Simultaneous Realization of Multilayer Interphases on a Ni-Rich NCM Cathode and a SiOx Anode by the Combination of Vinylene Carbonate with Lithium Difluoro(oxalato)borate

“…Currently, the theoretical specific capacity of conventional graphite anode materials is 372 mA h g –1 , with the Li + intercalation reaction occurring at 0.1 V (vs Li/Li + ). , Despite the commercialization of graphite anodes, new anode materials are being actively studied owing to the low energy density of conventional LIBs. Recently, the research and development of Si-based anode materials has surged because of their specific capacity, which is almost ten times greater than that of conventional graphite, via alloy reactions with Li + . − Nevertheless, such alloy reactions always pulverize Si-based anode materials through rapid volume expansion and contraction upon cycling. − Note that once Si-based anode materials are pulverized, the released dead Si-based anode material results in a significant decrease in the specific capacity. Simultaneously, electrolyte decomposition is accelerated at the interface of the Si-based anode (from pulverization), causing a rapid decline in the retention owing to an increase in resistance. , …”

Rational Design of Multifunctional Surface Modification for Ni-Rich Layered Cathodes of Lithium-Ion Batteries

“…Although numerous factors could influence the energy density of LIBs, it is broadly known that the energy density of the cell is closely related to the specific capacity and voltage, which can be realized by electrode materials. − In this regard, the exploration of electrode materials, which can offer greater specific capacity with a higher voltage than that of conventional electrode materials, has increased exponentially over the past years. In terms of cathode materials, there has been a marked increase in intensive research focusing on advanced cathode materials that can achieve higher specific capacity than that of the conventional layered LiCoO 2 (LCO) material, especially focusing on LiNi x Co y Mn z O 2 (LNCM) cathode materials with a high Ni content. − The Ni-rich LNCM cathode material is considered to be an advanced cathode material, in which part of the Co component in the LCO cathode material is replaced with Ni and Mn due to its desirable electrochemical behaviors.…”