Enhanced Polysulfide Trapping and Conversion by Amorphous-Crystalline Heterostructured MnO2 Interlayers for Li-S Batteries

Thepractical application of lithium-sulfur batteries (LSBs) isstill hindered by several technical issues, including severe polysulfideshuttling and sluggish redox kinetics, which reduces the sulfur utilizationand further results in low energy density. Herein, amorphous-crystallineheterostructured MnO2 (ACM) prepared through a simple calcinationprocess was employed as the functional interlayer to play a doublerole as effective trapper and multifunctional electrocatalyst forLSBs. ACM not only combines the strong sulfur chemisorption of theamorphous MnO2 (AM) and fast Li+ transportationof the crystalline MnO2(CM) but also accelerates the interfacecharge transfer at the amorphous/crystalline interfaces. The LSBswith such unique interlayer exhibited an excellent rate performanceof 1155.5 mAh center dot g(-1) at 0.2 C and 692.9 mAh center dot g(-1) at 3 C and a low decay rate of 0.071% per cycle over500 cycles at 0.5 C. Even for a high sulfur loading of 5 mg center dot cm(-2) at 0.1 C, a high capacity retention of 92.3% couldalso be achieved after 100 cycles. The concept of amorphous-crystallineheterostructures prepared by crystallization regulation might alsobe used for other electronic devices and catalyst designs.