Cross-linked binder enables reversible volume changes of Si-based anodes from sustainable photovoltaic waste silicon

Abstract

Although silicon is regarded as the appealing anode for next-generation lithium-ion batteries (LIBs) due to its high specific capacity, its practical application is still hindered by large volume expansion upon lithiation. To tackle the issue, novel binders have been developed in recent years. Herein, we construct a three-dimensional cross-linked binder by forming hydrogen bonds between carboxymethyl cellulose (CMC) and ethylenediaminetetraacetic acid disodium (EDTA-2Na) with EDTA-2Na further coordinated to calcium ions (Ca2+). Compared with the bare CMC binder, the cross-linked CMC/EDTA-Ca2+ binder exhibits a better mechanical property and higher adhesion strength, which enables reversible volume change and improves the cycling performance of Si/C anode (80.7% retention after 380 cycles at 1 A g−1). Meanwhile, low-cost and abundant photovoltaic waste silicon was recycled as Si source to fabricate Si/C anode. This work provides a sustainable route to fabricate Si anode by recycling photovoltaic Si and a practical method to stabilize Si anode by constructing a cross-linked binder.