Low-Cost and "Green" Avenue toward Large-Scale Synthesis of In Situ Passivated Si Nanoflakes and Construction of Binder-Free Electrodes

Yanmin Zhou ¹, Weiyuan Zhao ¹, Zhen Xing ¹

⁰School of Physics and Materials Science, Nanchang University, 999 Xuefu Avenue, Nanchang 330031, China.

Acs Applied Materials & Interfaces +

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July 2, 2025

View abstract on PubMed

Summary

We developed a bead-grinding method to create silicon nanoflakes with pyromellitic acid (PMA) for lithium-ion batteries. This improves initial Coulombic efficiency and cyclic stability, paving the way for practical silicon anodes.

Area Of Science

Materials Science
Electrochemistry
Nanotechnology

Background

Silicon anodes offer high theoretical capacity for lithium-ion batteries but suffer from high cost and poor reproducibility.
Existing silicon anode materials face challenges with volume expansion and unstable solid-electrolyte interphase (SEI) formation during cycling.
Developing cost-effective and stable silicon anode materials is crucial for advancing next-generation energy storage.

Purpose Of The Study

To address the limitations of silicon anodes by developing a facile and scalable method for producing modified silicon nanomaterials.
To enhance the electrochemical performance, particularly initial Coulombic efficiency (ICE) and cyclic stability, of silicon anodes.
To investigate the role of in situ bonded pyromellitic acid (PMA) and carboxymethyl cellulose sodium (CMC) in improving silicon anode performance.

Main Methods

A bead-grinding technique was employed to synthesize silicon nanoflakes from micron-sized silicon.
Pyromellitic acid (PMA) molecules were in situ bonded to the silicon nanoflakes to passivate surfaces and form an artificial SEI.
Binder-free electrodes were fabricated, with further modification using carboxymethyl cellulose sodium (CMC) to enhance electronic contact and electrode integrity.

Main Results

The modified silicon nanoflakes exhibited an improved initial Coulombic efficiency (ICE) of 71.7% (vs. 62.4% for bare Si) and an initial charge capacity of 2347.2 mAh g<sup>-1</sup>.
Superior cyclic stability was demonstrated, with a charge capacity of 1087.6 mAh g<sup>-1</sup> retained after 500 cycles at 400 mA g<sup>-1</sup>.
The addition of CMC further boosted the ICE to 80% and the Si-PMA-CMC electrode maintained 1124.6 mAh g<sup>-1</sup> after 300 cycles at 50 °C.

Conclusions

The facile bead-grinding technique coupled with in situ PMA modification offers a scalable route to high-performance silicon anodes.
The bonded PMA acts as a protective layer, enhancing stability and enabling binder-free electrode fabrication.
The synergistic effect of PMA and CMC creates elastic networks, significantly improving the electrochemical performance and practical applicability of silicon anodes for lithium-ion batteries.

Keywords:

binder-free electrode lithium-ion battery micron silicon material pyromellitic acid silicon-nanoflake