# Porous alloying-type particles for practical lithium-ion battery anodes

## TL;DR

This review explores how porous structures in alloying-type anodes can improve the performance and lifespan of high-energy lithium-ion batteries.

## Contribution

The paper provides a comprehensive analysis of porous alloying-type anodes, emphasizing pore functionality and scalable synthesis methods for practical battery applications.

## Key findings

- Intraparticle pores are more effective than interparticle pores in managing volume changes during battery cycling.
- Bottom-up, top-down, and transcription approaches are key methods for fabricating scalable porous anodes.
- Advanced binders and electrolytes help stabilize porous anodes in practical battery cells.

## Abstract

Li-alloying-type anodes (Si, Sn, Ge, etc.) are potential candidates for high-energy lithium-ion batteries (LIBs), offering outstanding Li-storage capacity. However, their practical use is hampered by severe volume fluctuations during cycling, which lead to particle pulverization, an unstable interphase, and thus a shortened lifespan. Engineered porous structures have emerged as being key to solving these challenges. This review focuses on the porous alloying-type particles (ATPs) for LIB anodes. First, the structural evolution of ATPs with or without pores during lithiation is analysed using a graphite anode as a reference, highlighting the critical role of intraparticle rather than interparticle pores. Synthetic methodologies for fabricating porous ATPs are summarized and categorized into bottom-up, top-down, and transcription approaches, with special emphasis on their scalability for practical application. Recent progress in elucidating the in-cell evolution of pores and the key function of intraparticle pores is discussed in detail, emphasizing the contrasting effects of open versus closed pores. We also review representative diagnostic techniques for quantitative pore characterization, and the advanced binders or electrolytes that stabilize porous ATPs in the context of practical pouch or cylindrical cells. Lastly, we discuss cell-level considerations and operating procedures, outlining future research directions toward post-intercalation anodes for both liquid- and solid-state LIBs.

This review discusses porous alloying-type anodes for high-energy lithium-ion batteries, highlighting how engineered pores address expansion. It covers pore functionality, synthesis, characterization and their integration into practical cells.