Carbon-free sulfur-based composite cathode for advanced Lithium-Sulfur batteries: A case study of hierarchical structured CoMn2O4 hollow microspheres as sulfur immobilizer

摘要

The intrinsic insulation, structural instability and deprived reactivity induced by "shuttle effect" and low volumetric capacity put forward a formidable challenge for future practical application of Lithium-Sulfur batteries. Herein, 3D hierarchical structured CoMn2O4 hollow microspheres assembled by primary nanocrystalline, as carbon-free sulfur hosts, were prepared and employed to fabricate the CoMn2O4-S composite. The unique hollow architectures not only could offer enough space for accommodating sulfur and relieving volume expansion of sulfur during cycles, but also provide favorable ion transport and sufficient active sites for catalytic conversion of polysulfides. The CoMn2O4 possesses high electronic conductivity and strong polar feature, allowing a high discharge capacity and good cycle stability by restraining shuttle effect of polysulfides. More importantly, CoMn2O4-S composite shows a high tap density of 1.73 g cm(-3), due to employment of the heavy CoMn2O4 as sulfur host, thus the electrode could deliver a high volumetric capacity of 907.1 mAh cm(-3) even at 1600 mA g(-1). (C) 2019 Elsevier Ltd. All rights reserved.