Porous carbon materials derived from discarded COVID-19 masks via microwave solvothermal method for lithium‑sulfur batteries

Yuwen, Chao; Liu, Bingguo; Qiu, Rong; Zhang, Libo; Guo, Shenghui

doi:10.1016/j.scitotenv.2022.152995

Cited by 35 publications

(22 citation statements)

References 42 publications

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“…However, there are several recent studies using PP-derived masks as carbon precursors for preparing carbon materials, which fibril structures were all successfully retained upon pyrolysis, while the mechanical properties of resulting carbon fibers remain not clear. [56][57][58] In this work, PP parts with much thicker walls were employed. As polymer crosslinking is fundamentally important for enabling the polymer-to-carbon conversion, it is important to first obtain a systematic understanding about the crosslinking kinetics of 3D printed PP.…”

Section: Resultsmentioning

confidence: 99%

Additive Manufacturing of Carbon Using Commodity Polypropylene

et al. 2023

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focused on research and product development of carbon-based materials, exemplified by the discoveries of fullerene, [10] carbon nanotubes [11] and graphene, [12] as well as fabrication of porous carbon [13] and carbon black additives for many commercial applications. [14] However, most industries can only employ these functional carbon materials as fillers, necessitating additional components, often polymer matrices, for imparting processability. [15,16] The presence of matrix materials can greatly diminish many intrinsic advantages of carbons, leading to compromised material performance. Furthermore, necessary steps of mixing and processing in composite manufacturing may lead to high energy consumption and carbon footprint, resulting in an enormous negative impact on the environment. Enabling ondemand manufacturing of carbons with controlled macroscopic structures is necessary to unlock their full potential in various applications, while addressing urgent societal challenges including climate change and environmental sustainability.Generally, creating structured carbon materials rely on the use of polymer precursors, combined with pyrolysis-based approaches to allow their conversion to carbon materials. [17][18][19] A common example in this area is carbon fiber manufacturing, which uses polyacrylonitrile (PAN) as a carbon precursor and involves multiple processing steps, including fiber spinning, drawing, thermal stabilization/crosslinking and carbonization. [20] Alternatively, many other carbon precursors have been reported, including pitch-based chemicals, [21] lignin, [22,23] cellulose, [24,25] polyethylene (PE), [26][27][28] polypropylene (PP) [29,30] and polybenzoxazines. [31,32] While these chemical can be effectively converted to carbons, the scope of most work in the area of structured carbon production is associated with fibril materials; [33] the ability of manufacturing carbon with complex architectures at macroscopic scale is largely underexplored.In recent years, additive manufacturing (AM) has attracted significant attention in both academic research labs and largescale manufacturing facilities, leading to wide recognition as a key future manufacturing technology. [34] AM can create products through layer-by-layer addition without the need for tools and molds, which is also inherently less wasteful than traditional subtractive-based methods due to its significantly Carbon materials are essential to the development of modern society with indispensable use in various applications, such as energy storage and high-performance composites. Despite great progress, on-demand carbon manufacturing with control over 3D macroscopic configuration is still an intractable challenge, hindering their direct use in many areas requiring structured materials and products. This work introduces a simple and scalable method to generate complex, large-scale carbon structures using easily accessible materials and technologies. 3D-printed, commercial polypropylene (PP) parts can be thermally stabilized through cracking-faci...

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Section: Resultsmentioning

confidence: 99%

Additive Manufacturing of Carbon Using Commodity Polypropylene

et al. 2023

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“…Yuwen et al ( 2022 ) completed the overall sulfonation and oxidation of the waste mask within 8 min by microwave solvothermal method based on the excellent microwave absorption capacity of concentrated sulfuric acid. The sulfonated sample was made into porous carbon with a high surface area, and the carbon yield was up to 54 wt% after self-activated pyrolysis in low-flow argon at 900 °C (Yuwen et al 2022 ). Figure 7a shows the diagram of cross-linking, carbonization, and activation of PP fiber.…”

Section: Thermochemical Technologymentioning

confidence: 99%

Disposal and resource utilization of waste masks: a review

Cui

Zhang

et al. 2023

Environ Sci Pollut Res

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Waste masks pose a serious threat to the environment, including marine plastic pollution and soil pollution risks caused by landfills since the outbreak of COVID-19. Currently, numerous effective methods regarding disposal and resource utilization of waste masks have been reported, containing physical, thermochemical, and solvent-based technologies. As for physical technologies, the mechanical properties of the mask-based materials could be enhanced and the conductivity or antibacterial activity was endowed by adding natural fibers or inorganic nanoparticles. Regarding thermochemical technologies, catalytic pyrolysis could yield considerable hydrogen, which is an eco-friendly resource, and would mitigate the energy crisis. Noticeably, the solvent-based technology, as a more convenient and efficient method, was also considered in this paper. In this way, soaking the mask directly in a specific chemical reagent changes the original structure of polypropylene and obtains multi-functional materials. The solvent-based technology is promising in the future with the researches of sustainable and universally applicable reagents. This review could provide guidance for utilizing resources of waste masks and address the issues of plastic pollution.

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“…The current chemical methods for recycling plastics are mainly through pyrolysis, 3 However, the direct pyrolysis results in low added value due to the wide distribution of the product. In addition, the content of polyethylene terephthalate in discarded medical masks is close to 16 wt.%, which also does not meet the requirements of companies for pyrolysis raw materials 4 . Therefore, there is an urgent need for an appropriate method to solve the discarded medical masks pollution while achieving higher returns.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the content of polyethylene terephthalate in discarded medical masks is close to 16 wt.%, which also does not meet the requirements of companies for pyrolysis raw materials. 4 Therefore, there is an urgent need for an appropriate method to solve the discarded medical masks pollution while achieving higher returns.…”

Section: Introductionmentioning

confidence: 99%

Discarded COVID ‐19 masks‐derived‐doped porous carbon for lithium‐sulfur batteries

Qiu

Yuwen

Liu

et al. 2022

Intl J of Energy Research

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Summary Despite the high theoretical capacity and energy density of lithium‐sulfur (Li‐S) batteries, the development of Li‐S batteries has been slow due to the poor electrical conductivity and the shuttle effect of the electrode materials, resulting in low sulfur utilization and fast long‐term cycling capacity decay. The modified carbon materials are often used as sulfur hosts to significantly improve the cycling performance of the materials, but also bring high‐cost issues. Here, the porous carbon materials are synthesized quickly and conveniently by the microwave cross‐linking method using discarded medical masks as carbon sources and concentrated sulfuric acid as solvent. However, poor surface and structural properties limit the application of materials. The porous carbon material is modified with p‐toluene disulfide and urea as the sulfur and nitrogen sources by the microwave cross‐linking method, which not only improves the porosity and specific surface area of the porous carbon material, but also improved the electrical conductivity and interlayer spacing of the material. As synthesized SN‐doped porous carbon is employed as the sulfur host, which exhibits a high discharge capacity (1349.3 mAh g −1 ) at 0.1°C, the S‐porous C/S, N‐porous C/S, and SN‐porous C/S can maintain 78.1, 43.9, and 59.5% of the initial capacity after 500 cycles. The results indicate that the doping of S and N atoms provides sufficient active sites for the chemisorbed lithium polysulfides (LiPSs) to improve the reaction kinetics of the materials.

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Porous carbon materials derived from discarded COVID-19 masks via microwave solvothermal method for lithium‑sulfur batteries

Cited by 35 publications

References 42 publications

Additive Manufacturing of Carbon Using Commodity Polypropylene

Additive Manufacturing of Carbon Using Commodity Polypropylene

Disposal and resource utilization of waste masks: a review

Discarded COVID ‐19 masks‐derived‐doped porous carbon for lithium‐sulfur batteries

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