Three-Dimensional Porous Si@SiOx/Ag/CN Anode Derived from Deposition Silicon Waste toward High-Performance Li-Ion Batteries

Abstract

The application of photovoltaic (PV) solid waste to the field of lithium-ion batteries is deemed to be an effective solution for waste disposal, which can not only solve the problem of environmental pollution but also avoid the loss of secondary resources. Herein, based on the volatile deposited waste produced by electron beam refining polysilicon, a simple and environmentally friendly method was designed to synthesize P-Si@SiOx/Ag/CN as an anode material for lithium-ion batteries. Remarkably, the presence of silver and the formation of a carbon−nitrogen network can enhance the electrical conductivity of the composite and boost the transport efficiency of lithium ions. Furthermore, the porous Si@SiOx structure is generated by silverassisted chemical etching (Ag-ACE), and the carbon−nitrogen grid architecture is formed after lyophilization with NaCl as a template, which can jointly provide sufficient buffer space for the volume change of silicon during lithiation/delithiation. Benefitting from these advantages, the P-Si@SiOx/Ag/CN anode exhibits outstanding cycling performance with 759 mA h g −1 over 300 cycles at 0.5 A g −1 . Meanwhile, the lithium-ion batteries employing the P-Si@SiOx/Ag/CN anodes present a superior rate capability of 950 mA h g −1 at 2 A g −1 and retain a high reversible specific capacity of 956 mA h g −1 at 1 A g −1 after 50 cycles. This work opens up a new economic strategy for the fabrication of high-performance silicon anodes and affords a promising avenue for the recycling of PV silicon waste.

Stress-Relief Engineering in a N-Doped C-Modified Hierarchical Nanoporous Si Anode with a Microcurved Pore Wall Structure for Enhanced Lithium Storage

“…Also, the other two peaks are associated with the bonds of Si–Si (99.79 eV) and Si–C (102.48 eV). In Figure e, a set of fitted peaks match the C–O, Si–O, and CO bonds (530.84, 532.76, and 533.04 eV), respectively. ,,, The peaks in the D (1366 cm –1 ) and G (1594 cm –1 ) bands in the Raman spectrum of N-C@m-HNP Si (Figure f) correspond to disordered carbon and graphitic carbon, respectively. − The intensity ratio between peaks D and G ( I D / I G ) indicates the degree of graphitization of the carbon. , The higher the I D / I G value, the more disordered the carbon is and the poorer the crystallinity. The I D / I G of the carbon layer formed by polydopamine carbonization is 0.851, indicating that it has a significant degree of disorder.…”

“…The disappearance of these reduction peaks on the subsequent curves indicates the formation of the stable SEI layer. During the discharge stage of the second CV curve, the reduction peak at 0.18 V (vs Li/Li + ) corresponds to the formation of Li x Si and the sharp reduction peak at 0.01 V (vs Li/Li + ) is attributed to the coupling effect of the continuous alloying reaction of Li–Si and the lithium insertion reaction of the carbon layer. − The apparent oxidation peaks at 0.33 V (vs Li/Li + ) and 0.55 V (vs Li/Li + ) in the charging stage correspond to the delithiation process of Li x Si. − The increase in the peak current of these redox peaks on the third CV curve indicates an improvement in the electrochemical reaction kinetics. These CV curves of the three anodes show the typical electrochemical behavior of the Si anode, and the specific reaction is as follows. Si + x Li + + x normale − ↔ Li x Si …”

“…However, Si anodes undergo a significant volume change (∼300%) during the lithiation/delithiation process, − leading to internal stress and various problems with active substance falling off the collector, instability of the solid electrolyte interface (SEI) layer, failure of the electrical connection between the active substance and the collector, and a decrease in battery capacity, conductivity, and cycle life. − To address these issues, many excellent studies have been reported, including the preparation of Si nanoparticles, , nanorods, nanowires, and nanotubes, the development of active-inertia systems, and the construction of porous structures. ,− Among these, reducing the particle size can stabilize the performance of Si anodes, but significant internal stress accumulates during multiple charges and discharges, eventually leading to battery failure. In contrast, the construction of porous structures can better stabilize the performance of Si anodes. − For example, Sohn et al prepared nonporous and porous micrometer-sized Si/C composite anodes by ball milling and alkaline etching . The initial specific capacity of the nonporous Si/C anode reached 2471 mAh g –1 , while that of the porous Si/C anode was only 1438 mAh g –1 due to the difference in Si content.…”

Scalable Synthesis of a Si/C Composite Derived from Photovoltaic Silicon Kerf Waste toward Anodes for High-Performance Lithium-Ion Batteries

“…Figure a,c presents the Nyquist curves of both the SKW and P-SKW@C anodes before cycling and after 50 cycles, respectively, with a frequency range of 0.01 Hz to 100 kHz and a voltage range of 0.01 to 2 V. The fitting parameters of Rs, Rf, and Rct correspond to the electrolyte impedance, SEI impedance, and charge transfer impedance by the equivalent circuit, respectively . Additionally, the capacitance of the interface and the Warburg resistance associated with the diffusion of Li + are denoted as CPE 1/2 and W 0 , respectively. , Table shows the relevant parameters for the simulation.…”

“…Metal oxide layers, such as zinc oxide, further enhance the mechanical performance of silicon-based anodes to suppress volume expansion. Besides, the synergistic effects of metal etching and coating have been explored to improve Li + /e – transport, form a more stable SEI film, and reduce volume changes, contributing to enhanced electrochemical and cycling performance. However, despite these advancements, the commercialization of these approaches still faces numerous challenges due to complex processing and costly raw materials.…”