Low-cost and scalable preparation of nano-Si from photovoltaic waste silicon for high-performance Li-ion battery anode

Abstract

Nano silicon (nano-Si)-based materials have been considered as promising anodes for next-generation Li-ion batteries (LIBs) because of their high specific capacity. However, a facile processing method of nano-Si with cheap Si sources is still lacking. Herein, we propose a facile, scalable and cost-effective route to produce nano-Si using a low-cost Si source from photovoltaic (PV) waste silicon. The nano-Si of 484 nm in [Formula: see text] can be easily produced using the PV waste Si by facile acid washing, heat treatment and sand milling steps. Compared with commercial nano-Si (120 nm), our low-cost nano-Si exhibits higher Coulombic efficiency (87.1%) and better cycling stability. The cycling stability of nano-Si can be obviously enhanced by using a carboxymethyl cellulose (CMC) binder and an electrolyte composed of 1 mol L[Formula: see text] LiPF6 in fluoroethylene carbonate (FEC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) (1:1:1). The nano-Si with CMC binder in 1 mol L[Formula: see text] LiPF6 FEC/EMC/DMC electrolyte could maintain a discharge capacity of 1488 mAh g[Formula: see text] after 200 cycles at 1 A g[Formula: see text]. Our work provides a promising, sustainable method to make high-performance nano-Si using a low-cost Si source.