# Recycling Silicon Scrap for Spherical Si-C composite as High-Performance Lithium-ion Battery Anodes

**Authors:** Bhagath Sreenarayanan, Marta Vicencio, Shuang Bai, Bingyu Lu, Ou Mao, Shiva Adireddy, Wurigumula Bao, Ying Shirley Meng  
**arXiv:** [2305.10545](https://arxiv.org/abs/2305.10545)  
**Date:** 2023-05-17  
**Summary page:** https://www.summarizepaper.com/en/paper/2305.10545v1/

## Key points

- Growth of semiconductor and solar industry has been exponential
- Significant amount of silicon waste generated by these industries
- Waste needs to be upcycled, recycled, or reused for circular economy
- Upcycled/recycled Si can be used as composite anode material in lithium-ion batteries
- Composite material has high Si content and loading, resulting in superior electrochemical performance
- Unique spherical jackfruit-like structure minimizes lithium inventory loss
- Si-based industrial waste offers controllable, scalable, and energy-efficient route for recycling/upcycling Si materials
- Opportunity to recycle valuable materials from photovoltaic and semiconductor sectors
- Previous approaches to upcycle silicon scrap have been complex and economically unfeasible at large scale
- Researchers focus on developing spherical Si-C 'jackfruit-like' composite materials using repurposed Si from semiconductor/solar waste

## Summary

The growth of the semiconductor and solar industry in the past two decades has been exponential, driven by the increasing computing and energy demands of the world. This growth has also resulted in a significant amount of silicon (Si) waste being generated by these industries. In order to achieve a sustainable world, it is crucial that this waste is upcycled, recycled, or reused to complete the circular economy chain. In this study, researchers demonstrate that upcycled/recycled Si can be used as a composite anode material with carbon for practical use in lithium-ion batteries. The composite material has a high Si content (~40 wt.%) and loading of 3-4 mAh/cm^2, resulting in superior electrochemical performance compared to conventional Si-C composites and pure Si. The unique spherical jackfruit-like structure of the Si-C composite minimizes total lithium inventory loss, further enhancing its performance. The use of Si-based industrial waste for high-performance Li-ion battery anodes offers a controllable, scalable, and energy-efficient route for recycling/upcycling Si materials. This approach addresses scalability and economic issues associated with Si-based anode materials for LIBs. Additionally, it presents an opportunity to recycle valuable materials from other industries such as photovoltaic and semiconductor sectors. Previous works have explored different methods to upcycle silicon scrap into value-added anode materials. However, most of these approaches involve complex routes and additional processing steps to reduce problems associated with pure silicon-based anodes. As a result, economically feasible large-scale production of upcycled silicon-based anodes has not been realized yet. In this study, the researchers focus on developing spherical Si-C 'jackfruit-like' composite materials through a scalable approach using repurposed Si from semiconductor/solar waste. The detailed process involves liquid milling on the Si waste to obtain pure Si powder with a desired particle size which is then mixed with carbon black and binder to form a slurry which is coated onto a copper foil and dried finally producing the desired composite anode material exhibiting excellent electrochemical performance enabling high cell energy density.