Millisecond Conversion of Photovoltaic Silicon Waste to Binder‐Free High Silicon Content Nanowires Electrodes

Abstract

High‐value recycling of photovoltaic silicon waste is an important path to achieve “carbon neutrality.” However, the current remelting and refining technology of Si waste (WSi) is tedious with high secondary energy consumption and repollution, and it can only achieve its relegation recycling. Here, an efficient and high‐value recycling strategy is proposed in which photovoltaic WSi is converted to high energy density and stable Si nanowires (SiNWs) electrodes for lithium‐ion batteries (LIBs) in milliseconds. The flash heating and quenching (≈2100 K, 10 ms) provided by an electrothermal shock drive directional diffusion of Si atoms to form SiNWs within the confined space between graphene oxide films. As a result, the SiNWs self‐assemble to form a conductive SiNWs–reduced graphene oxide composite (SiNWs@RGO). When applied as a binder‐free anode for LIBs the SiNWs@RGO electrode exhibits an ultrahigh initial Coulombic efficiency (89.5%) and robust cycle stability (2381.7 mAh g−1 at 1 A g−1 for more than 500 cycles) at high Si content of 76%. Moreover, full LIBs constructed using the commercial Li[Ni0.8Co0.16Al0.04]O2 cathode exhibit impressive cycling performance. In addition, this clean high‐value recycling method will promote economic, environmentally friendly, and sustainable development of renewable energy.

Zero‐Strain High‐Capacity Silicon/Carbon Anode Enabled by a MOF‐Derived Space‐Confined Single‐Atom Catalytic Strategy for Lithium‐Ion Batteries

“…The XRD pattern of the Si NDs⊂MDN displays three typical diffraction peaks corresponding to the (111), (220), and (311) planes of Si crystal (JCPDS 27-1402), [37][38][39] respectively, suggesting Si nanodots are in crystalline phase. Raman spectrum of the Si NDs⊂MDN and MDN (Figure 2b) exhibits typical peaks corresponding to Si, and D and G bands of graphitic carbon, [37,38,40] respectively, in good agreement with the XRD characterization. Brunauer−Emmett−Teller (BET) analysis evidences the coexistence of micropores, mesopores and macropores in the structure of the MDNs, with a specific surface area (S BET ) of 470.3 m 2 g −1 and a total pore volume of 0.2528 cm 3 g -1 (Figure 2c; Table S3, Supporting Information).…”

“…The content of C, N, Zn, and Si elements in the composite sample is 64. confirming that Zn element in the MDNs exists as single atoms. The XRD pattern of the Si NDs⊂MDN displays three typical diffraction peaks corresponding to the (111), (220), and (311) planes of Si crystal (JCPDS 27-1402), [37][38][39] respectively, suggesting Si nanodots are in crystalline phase. Raman spectrum of the Si NDs⊂MDN and MDN (Figure 2b) exhibits typical peaks corresponding to Si, and D and G bands of graphitic carbon, [37,38,40] respectively, in good agreement with the XRD characterization.…”

Constructing a Sheet-Stacked Si/C Composite by Recycling Photovoltaic Si Waste for Li-Ion Batteries

“…Xi et al synthesized PSi@SiO x /nano-Ag composites with artificial nano/micropores in the lamellar and native SiO x layer on the surface to relieve volumetric expansion. Overall, significant progress has been made with the recycling and utilization of Si waste to prepare Si-based anode materials. − However, although recent research studies already focus on the oxidation layer and the primary morphology, related research studies based on inherent materials advantages are still insufficient. Further exploration is needed to ensure that the raw material has advantages in scale utilization.…”

Recycling Waste Al–Si Alloy for Micrometer-Sized Spongy Si with High Areal/Volumetric Capacity and Stability in Lithium-Ion Batteries

“…To address the problem of fossil fuel energy and attain the carbon-neutral goal, conversion and storage of renewable energy, as well as high-value utilization of secondary resources, will become important development directions in the future. − As an important energy storage device, lithium-ion batteries (LIBs) attempt to fabricate electrodes from the waste of secondary resources that has attracted tremendous interest, particularly for the silicon (Si) anode, which is regarded as the most promising candidate for the anode of next-generation LIBs with high energy density due to its extremely high theoretical specific capacity (3579 mAh g –1 ) …”