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Recently, Professor Zhu Yanwu of the University of Science and Technology of China has used fullerene as a precursor to develop and design a nitrogen-doped porous carbon with excellent energy storage properties. The research results were published in Advanced Materials (DOI: 10.1002/adma.201603414) published on December 19.
Due to its high specific surface area and a large number of reactive sites, nitrogen-doped porous carbon materials have attracted wide attention as electrode materials and catalyst materials for electrochemical energy storage materials such as lithium ion batteries and supercapacitors, but nitrogen-doped form control has been A difficult point.
Zhu Yanwu's team had previously produced ultra-capacitor carbon electrode materials with excellent performance by activating potassium oxide-coated graphene oxide with potassium hydroxide. Based on the previous work, the team obtained porous carbon with good conductivity and high specific surface area by activating fullerene, a nanocarbon unit with a certain size and structure. It was found that when a relatively high proportion of potassium hydroxide is used for treatment, a vigorous activation process can break down the fullerene molecule and obtain carbon quantum dots. When the process is further optimized and ammonia gas is introduced during the activation process, nitrogen-doped porous carbon with different nitrogen doping amounts can be prepared. Because fullerene itself has a five-membered ring and a six-membered ring carbon structure, the main nitrogen form of the nitrogen-doped porous carbon is pyridine nitrogen and pyrrole nitrogen, among which pyrrole nitrogen is the main component. The calculation results show that the adsorption capacity of lithium ions due to the five-membered ring structure is larger than that of graphene. At the same time, pyrrole nitrogen and pyridine nitrogen, especially pyrrole nitrogen, greatly increase the adsorption capacity of lithium ions. The high specific surface area of ​​the material and the large number of topological defects make it possible to exhibit excellent rate performance.
When the material is used as a negative electrode material of a lithium ion battery, its reversible capacity reaches 1900 mAh/g at a current of 100 mA/g, and a reversible capacity of 600 mAh/g is still maintained after 800 cycles at a current of 2 A/g. This study not only obtained a new nitrogen-doped porous carbon material with excellent energy storage properties, but also provided a controllable nitrogen doping system for studying the application and mechanism of carbon materials in other fields such as catalysis.
The first author of the dissertation talks about Qi Qi and Qi Ni. The research work has been supported by funds from the Youth 1000 Program, the Natural Science Foundation of China, the Collaborative Innovation Center for Energy and Materials Chemistry, and the Synchrotron Radiation Fund.
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