Recently, Wu Zhongshuai, a researcher in the 2D Materials and Energy Device Innovation Special Zone Research Group of the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, has developed a 3D graphene / carbon nanotube porous aerogel material and applied it to the sulfur of lithium-sulfur batteries. The elementary carrier and the intermediate layer are integrated with a positive electrode to obtain a lithium-sulfur battery with high volume energy density and excellent cycle stability. Related research results were published in "Nano Energy".
Lithium-sulfur batteries have high-quality theoretical energy density (2600Wh / kg) and high volume energy density (2800Wh / L), and are considered to be a very promising high-specific energy battery. However, due to the low mass density of sulfur (2.07g / cm 3), poor conductivity (5 × 10 -30 S / cm), large volume expansion of active materials during charging and discharging (78.7%), and severe polysulfide shuttles, etc. The problem is that although its mass density is high, its volume energy density is generally low and its cycle performance is poor, which greatly limits the practical application of lithium-sulfur batteries. Therefore, how to simultaneously improve the mass and volume energy density of lithium-sulfur batteries and extend their cycle life is one of the bottlenecks in the current application research of lithium-sulfur batteries.
The research team developed a three-dimensional graphene / carbon nanotube porous aerogel material, and simultaneously applied it to the sulfur element carrier and intermediate layer of lithium-sulfur batteries, and successfully built a self-supporting, metal-free current collector integrated anode material. The integrated cathode material has high compaction density, excellent electrical conductivity, and good mechanical flexibility. It not only achieves a high volume sulfur load (1.64g / cm 3), but also significantly improves the volume energy density of lithium-sulfur batteries (1615Ah / L), and effectively inhibited the polysulfide shuttle effect. Under the condition of a large current density of 2C, the battery can stably circulate 500 times, and the capacity has almost no attenuation, showing excellent cycle stability. This design strategy of integrated anode structure with sulfur element carrier and intermediate layer provides new ideas for the construction of high volume energy density and long cycle life lithium-sulfur batteries.