Dalian Institute of Chemical Technology has made progress in the application of graphene aerogels to high-volume-energy lithium-sulfur batteries

by:CTECHi     2021-08-10

Recently, Wu Zhongshuai, researcher of the 2D Materials and Energy Device Innovation Special Zone Research Group of Dalian Institute of Chemical Physics, Chinese Academy of Sciences, and his team developed a 3D graphene/carbon nanotube porous aerogel material and applied it to lithium sulfur The sulfur element carrier and the intermediate layer of the battery are integrated with the positive electrode to obtain a lithium-sulfur battery with high volume energy density and excellent cycle stability. Related research results were published on NanoEnergy. Lithium-sulfur battery has high-quality theoretical energy density (2600Wh/kg) and high volume energy density (2800Wh/L), and is considered to be a very promising high specific energy battery. However, due to the problems of low mass density (2.07g/cm3), poor conductivity (5×10-30S/cm), and large volume expansion of active materials (78.7%) during charging and discharging, and serious polysulfide shuttles, the sulfur element has problems. As a result, although the mass density is high, the volume energy density is generally low and the cycle performance is poor, which greatly limits the practical application of lithium-sulfur batteries. Therefore, how to simultaneously improve the mass and volumetric energy density of lithium-sulfur batteries and extend their cycle life is one of the bottlenecks in the application research of lithium-sulfur batteries. The research team developed a three-dimensional graphene/carbon nanotube porous aerogel material and applied it to the sulfur element carrier and intermediate layer of lithium-sulfur batteries at the same time, successfully constructing a self-supporting, metal-free current collector integrated cathode material. The integrated cathode material has high compaction density, excellent electrical conductivity, and good mechanical flexibility. It not only achieves a high volumetric sulfur loading (1.64g/cm3), but also significantly improves the volumetric energy density of lithium-sulfur batteries (1615Ah/ L), and effectively inhibit the shuttle effect of polysulfides. Under the condition of a large current density of 2C, the battery can be cycled stably for 500 cycles, and the capacity is almost not attenuated, showing excellent cycle stability. The design strategy of the integrated positive structure of the sulfur element carrier and the intermediate layer provides a new idea for constructing a lithium-sulfur battery with high volume energy density and long cycle life. The above work was funded by the National Natural Science Foundation of China and the National Key Research and Development Program.

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