Abstract
In the past decade, the rising development of lithium ion batteries (LIBs) has been recognized as a tidal current for solving energy storage related issues. Under this technical billow, the demands of active materials with lower environmental impact and higher energy density are considered as the criteria for LIBs materials. Especially for anodic material, the present carbon-based electrode is limited in the potential applications with high capacity because of its theoretic capacity (372 mAh/g). To achieve the goal for high capacity anodes, silicon (Si) with 3590 mAh/g theoretical capacity meets the requirement by forming Li15Si4 phase during cycling processes to replace present conventional carbon-based batteries. However, the capacity fading caused by the intrinsic drawbacks of volumetric expansion and continuous formation of solid electrolyte interphase hinders the dissemination of Si-based LIBs. To overcome the disadvantages of Si, numerous studies have endeavored (1) to shrink Si particles to nanometer scales by using various morphology-chemical synthesis techniques, (2) to wrap or mix conductive additives onto particles or into slurries, and (3) to add electrolyte additives. Unfortunately, the as-mentioned methods mostly fail to accommodate the cost-effectiveness of commercialization and low pollution of environmental friendliness. In the pursuit of low cost and high environmental friendly anode material, a distinct resource of Si-based anode material is explored in this study. The recycled material is extracted from the cutting waste fluid produced in solar panel industry. After purification technology of chemical rinsing and physical separation, the obtained composites show much larger particle size than commonly nanolized Si particles, and possess the abundant organic bonds and native oxide on the surface of particle. Unlike conventional methods to focus on the synthesis process of powder, the as-prepared electrodes will be treated via various surface modifications, including techniques of carbon deposition and atmospheric pressure plasma jet. The combined processing reduces the capacity degradation by interfacial control to convert the surface bonds with the effectiveness to suppress the growth of SEI, and then maintain the stabilization of electrode during cycling. In addition, the entire electrode collocates with conductive agent and electrolyte additive to provide the conductivity and to improve the internal SEI formation. Overall, the developed techniques of surface modifications are not only scalable, simple, low-cost and environmental friendly but also effective to achieve the excellent performance with high capacity. It is expected for similar potential usage in others battery system. The selected recycled waste for anodic material should be applicable and suitable for the future blueprint in the commercialization for LIBs.