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The preparation of high-quality hard carbon Electrospun Nanofbers from low-cost coal pitch (CP), especially flexible thin films of HCNFs, is an eternal pursuit of researchers. However, the low softening point (LSP) property of CP itself severely constrains its inherent bottleneck. In view of this, Prof. Changzhou Yuan of Jinan University introduced a unique approach to improve the flexibility and performance of rigid carbon Electrospun Nanofbers to overcome the challenges posed by the inherent properties of coal pitch. The prepared rigid carbon Nanofiber Membrane has an optimized structure and excellent electrochemical properties. The related research results are summarized as “Construction of Low-Softening-Point Coal Pitch Derived Carbon Nanofiber Films as Self-Standing Anodes Toward a New Generation of Carbon Nanofiber Films”. The research results were published in the journal Advanced Functional Materials under the title of “Construction of Low-Softening-Point Coal Pitch Derived Carbon Nanofiber Films as Self-Standing Anodes Toward Sodium Dual-Ion Batteries”.
The main point of this paper
1. In this study, the application of low softening point coal pitch-derived carbon Nanofiber Membrane in sodium bi-ionic batteries was investigated, and a novel self-supporting anode material was proposed.
2. Hard carbon Electrospun Nanofbers with excellent electrochemical properties were successfully prepared by Bi(NO3)3-5H2O-assisted electrospinning -carbonization process.
3. It is shown that the HCNFs-1.2 film exhibits a high specific capacity of up to 300 mAh g-1 and good cycling stability in sodium-ion batteries, and the capacity retention rate reaches 90% after 200 charging and discharging cycles.
4. In addition, Nanofiber Membrane also exhibits excellent charge/discharge performance at high multiplicity, indicating its potential application value in the field of energy storage.
What is the significance of using low softening point coal pitch to prepare Nanofiber Membrane?
1. Cost-effectiveness:
Low softening point coal pitch is an inexpensive and abundant precursor, making it a viable option for the large-scale production of carbon Electrospun Nanofbers, which is critical for commercial applications.
2. High Carbon Content:
Coal pitch has a high carbon content, which facilitates the synthesis of hard carbon Electrospun Nanofbers with desirable electrochemical properties, especially in energy storage applications.
3. Challenges and solutions:
The low softening point property poses a challenge during high-temperature carbonization as it tends to soften and lose fiber morphology. However, innovative treatments such as non-molten pre-oxidation can transform it from a thermoplastic to a thermosetting material, resulting in the successful fabrication of stable Electrospun Nanofbers structures.
4. Performance enhancement:
Appropriate structural modification of the obtained HCNFs can improve the sodium storage performance and make them suitable for use as self-supporting anodes in sodium double-ion batteries (SDIBs)
1.Electrospinning:
The process begins by electrospinning a solution containing coal pitch and polyvinylpyrrolidone (PVP) as spinning aids. the addition of Bi(NO3)3-5H2O plays a crucial role in electrospinning, helping to stabilize the morphology of the fibers and preventing fusion between the fibers, which is a common problem when working with A common problem when using low softening point materials.
2. Pre-oxidation:
After electrospinning, the Electrospun Nanofbers mats are pre-oxidized at a temperature of approximately 230 °C. The Electrospun Nanofbers mats are then pre-oxidized at a temperature of about 30 °C. During this process, Bi(NO3)3-5H2O decomposes to form bismuth oxide nanoparticles distributed on the surface of the Electrospun Nanofbers. This pre-oxidation process partially oxidizes the polymer fibers, reduces the amount of gas released during the subsequent carbonization process, and helps maintain the fiber structure.
3. Carbonization:
The pre-oxidized Electrospun Nanofbers were subsequently carbonized. The temperature is gradually increased at a controlled rate to 600 °C, followed by a high temperature annealing at 1200 °C. This carbonization process converts the organic material into an organic material. This carbonization process converts the organic material to carbon, and the presence of bismuth oxide helps to inhibit the melting of the fibers, allowing them to maintain their fibrous morphology.
4. Formation of porous structures:
The method also promotes the formation of porous structures within the HCNFs. decomposition of Bi(NO3)3-5H2O produces nitrogen oxides that consume excess hydrogen during the carbonization process, altering the carbonization process and preventing excessive graphitization. This leads to the formation of porous and flexible carbon Nanofiber Membrane with enhanced electrochemical properties.
Originallink: https://doi.org/10.1002/adfm.202414761
