Dalian develops three-dimensional graphene to improve lithium-sulfur battery performance

It is understood that the research team of Wu Zhongshuai of Dalian Institute of Chemical Research and Development has developed a three-dimensional graphene / carbon nanotube porous aerogel material, which can greatly improve the performance of lithium-sulfur batteries, that is, high volume energy density and excellent cycle stability. Related research results were published in the international journal "Nano Energy".

All along, lithium-sulfur batteries are considered to be the most promising high specific energy batteries. However, due to the low mass density of sulfur, poor conductivity, large volume effect of active materials in the cycling process, and severe shuttle of polysulfide, the specific capacity is generally low and the cycling performance is poor, which greatly limits lithium The development of sulfur batteries. Therefore, how to improve the energy density and cycle performance of lithium-sulfur batteries is one of the current key research tasks of scientists.

Wu Zhongshuai's team applied the developed three-dimensional graphene / carbon nanotube porous aerogel material to the sulfur element carrier and intermediate layer of lithium-sulfur batteries, and successfully constructed a self-supporting, metal-free current collector integrated cathode material. The integrated cathode material has a very high compact density, excellent conductivity, and good mechanical flexibility, which can increase the capacity of the lithium-sulfur battery by 3 times, and effectively solves the problem of poor cycle stability caused by the shuttle of the polysulfide. Puzzles. The modified battery can circulate stably for 500 cycles even in a high-current environment, and its capacity is almost degraded.

In addition, it is worth mentioning that the transition element cake hexagonal tungsten trioxide material can also be used as a modifier of the electrode. Its large specific surface area and ultra-low volume expansion coefficient can increase the capacity of lithium-ion batteries by more than 6 times, and after multiple cycles, the battery capacity retention rate is still as high as 110.2%.