Indium Nitride Nanowires Modified Diaphragm to Enhance the Life of Li-ion Battery
Researchers Niu Zhiqiang and Wang Yijing of Nankai University and Professor Zhang Qiang of Tsinghua University introduced indium nitride nanowires into lithium-sulfur batteries through membrane modification, which can effectively inhibit the 'shuttle effect' of lithium-sulfur batteries and improve battery rate performance and cycling Performance, to achieve a significant increase in battery cycle life. Relevant results have been published in the December issue of 'American Chemical Society Nanomaterials'. Lithium-sulfur batteries have attracted much attention because of their extremely high theoretical specific capacity, rich sulfur content and low prices. However, in the electrochemical process of lithium-sulfur batteries, the 'shuttle effect' and the slow kinetic conversion caused by the polysulfide dissolved between the sulfur anode and the lithium anode seriously reduce the utilization of active sulfur, which leads to The rapid decay of capacity greatly reduces the service life of lithium-sulfur batteries. 'The so-called'shuttle effect' refers to that during the charge and discharge process, the polysulfide intermediates sprouted from the positive electrode dissolve into the electrolyte, pass through the diaphragm, diffuse to the negative electrode, and directly react with the lithium metal in the negative electrode, and finally cause The irreversible loss of effective substances in the battery, the attenuation of battery life, and the low coulombic efficiency.' Niu Zhiqiang analyzed that at present, people have adopted various methods to improve the above problems. The most common strategy is to use nanostructures with high specific surface area. Carbon materials are used to capture lithium polysulfide through physical restrictions; or polar materials are used to capture lithium polysulfide through chemical interaction. However, the non-polarity of carbon usually leads to poor cycle performance, and the low conductivity of polar materials leads to low sulfur utilization and poor rate performance. Therefore, it is necessary to develop an effective material preparation method that is simple but can significantly improve the cycle performance of sulfur cathodes while maintaining good rate performance. This is very important for lithium-sulfur batteries with long cycle life. 'The indium cations and electron-rich nitrogen atoms of indium nitride capture the generated polysulfides through strong chemical bonding; at the same time, the rapid electron transfer on the surface of indium nitride improves the dynamic conversion process of polysulfides. In this way, the dual function The indium nitride modified diaphragm seems to be a wall, which can effectively suppress the 'shuttle effect' in lithium-sulfur batteries.' Niu Zhiqiang analyzed that lithium-sulfur batteries with indium nitride modified diaphragms show excellent rate performance and cycling Performance, the capacity attenuation of each cycle after 1000 cycles is only 0.015%. This research has laid the foundation for the next development of high-stability lithium-sulfur batteries.