生物质基碳气凝胶及其在储能器件中应用研究进展

Research progress in biomass-based carbon aerogels in energy storage device

为提高生物质基碳气凝胶的电化学性能,促进其在储能领域的产业化应用,对储能器件领域用生物质基碳气凝胶材料进行了系统评述。首先介绍了目前制备生物质基碳气凝胶的主要方法,即凝胶炭化法、水热炭化法和直接炭化法,并对比分析了3种方法的优缺点。分别总结了3类生物质基碳气凝胶在超级电容器和锂离子电池等储能器件中的最新研究进展,包括未经改性的纯生物质基碳气凝胶以及通过金属掺杂和杂原子掺杂改性的复合生物质基碳气凝胶,并重点阐述了其材料设计和微观结构与电化学性能之间的关系。最后在对研究现状进行深入分析的基础上,展望了生物质基碳气凝胶未来的研究方向和发展前景,指出提高原料利用率、改善整体环保性以及调控结构性能将会成为今后的热点方向,而生物质基碳气凝胶也势必将作为一种新型的绿色电化学能源材料而得到蓬勃发展。

Significance With the increasing scarcity of oil,coal and other resources,the development of green and efficient energy storage materials has gradually become the focus of relevant research.Carbon aerogels have been recognized as one of the most promising candidate for energy storage materials due to its high porosity,low density,good electrical conductivity and high temperature resistance.Biomass materials are the most cost-effective,environmentally friendly and sustainable precursors for fabricating carbon aerogels.The preparation of biomass-based carbon aerogel and its application in the field of energy storage have attracted much research attention in the recent years.The release of China's"carbon peak and carbon neutralization"strategy further promotes its research and application.To foster the development of biomass-based carbon aerogels,a systematically overview on biomass-based carbon aerogels for energy storage devices was carried.Progress Based on the differences in raw material form,the preparation methods of biomass-based carbon aerogel are summarized as gel carbonization,hydrothermal carbonization and direct carbonization.Three preparation methods including the technological process,application range and advantages/disadvantages are compared and analyzed.At present,there are biomass-based carbon aerogels which are widely used,namely unmodified pure biomass-based carbon aerogels and composite biomass-based carbon aerogels modified by metal doping and heteroatom doping.This work summarizes the latest research progress in energy storage devices such as supercapacitors and lithium-ion batteries.Material design and microstructure are the main factors affecting the electrochemical performance of biomass-based carbon aerogel.Suitable doping and uniform nanostructure will help to improve its comprehensive performance.The energy storage device using this biomass-based carbon aerogel as the electrode shows superior rate capability and cycling performance during the test.In addition,relevant studies have shown that biomass-based carbon aerogels can also be used as electrodes for fuel cells,zinc-air batteries,and lithium-sulfur batteries.Some researchers attempted to use it to modify the battery separator and have achieved certain results.Conclusion and Prospect As a new type of functional aerogel,biomass-based carbon aerogels possess excellent properties of aerogel(high specific surface area,high porosity and low density),carbon materials(heat resistance and electrical conductivity)and biomass materials(economical and biodegradable).Based on these advantages,biomass-based carbon aerogel has been preliminarily applied in supercapacitors and some secondary batteries.In recent years,it has becomes one of the hotspot research fields in energy storage materials.Innovative research methods and theories are constantly emerging around the functional preparation,material characterization and product application of biomass-based carbon aerogels.However,there are still some uncertainties and challenges in the process of industrial production and application of biomass-based carbon aerogels.Future research can be focussed on the following aspects.①Development of new biomass precursors with more attention to be paided to the utilization rate of biomass materials and the impact of raw materials on the structure and properties of carbon aerogel.②Innovation and improvement of the preparation process of biomass-based carbon aerogels,aiming for large-scale production of carbon aerogels with uniform structure and excellent performance on the basis of reducing cost and energy consumption.③Replacement of man-made materials with natural renewable materials(such as silk fibroin extracted from cocoon silk),in forming the combination with biomass-based carbon aerogel,so as to improve the overall environmental protection of energy storage devices.④Further exploration into the influence mechanism of production process including composite process on biomass-based carbon aerogels to achieve controllable optimization of the microstructure and comprehensive properties of carbon aerogels so as to expand application into more prospective emerging material fields.