Boron Nitride Nanotube-Based Separator for High-Performance Lithium-Sulfur Batteries

To prevent global warming, ESS development is in progress along with the development of electric vehicles and renewable energy. However, the state-of-the-art technology, i.e., lithium-ion batteries, has reached its limitation, and thus the need for high-performance batteries with improved energy and power density is increasing. Lithium-sulfur batteries (LSBs) are attracting enormous attention because of their high theoretical energy density. However, there are technical barriers to its commercialization such as the formation of dendrites on the anode and the shuttle effect of the cathode. To resolve these issues, a boron nitride nanotube (BNNT)-based separator is developed. The BNNT is physically purified so that the purified BNNT (p-BNNT) has a homogeneous pore structure because of random stacking and partial charge on the surface due to the difference of electronegativity between B and N. Compared to the conventional polypropylene (PP) separator, the p-BNNT loaded PP separator prevents the dendrite formation on the Li metal anode, facilitates the ion transfer through the separator, and alleviates the shuttle effect at the cathode. With these effects, the p-BNNT loaded PP separators enable the LSB cells to achieve a specific capacity of 1429 mAh/g, and long-term stability over 200 cycles.

Automated summary

To overcome the technical barriers in the commercialization of lithium-sulfur batteries, a separator based on boron nitride nanotubes has been developed. This separator prevents dendrite formation on the lithium metal anode, facilitates ion transfer, and alleviates shuttle effect at the cathode. Through experiments, it has been shown that this separator enables lithium-sulfur batteries to achieve high specific capacity and long-term stability.