Editors: | Kongoli F, Kumar V, Aifantis K, Pagnanelli F |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2016 |
Pages: | 220 pages |
ISBN: | 978-1-987820-54-6 |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
High-energy rechargeable lithium-sulfur batteries are a promising energy storage system that has the potential to meet the ever-rising demand of our energy-consuming world. With elemental sulfur (S) as a cathode and lithium (Li) metal as an anode, Li-S batteries offer a theoretical specific energy of 2600 Wh kg-1, which is about five times that of the state-of-art lithium ion batteries. However, their commercialization has not come true yet due to the issues with the dissolution and diffusion of polysulfides in liquid organic electrolytes, which cause serious capacity degradation and low Coulombic efficiency. In addition, the insulating nature of S and lithium sulfide (Li2S), the final discharge product, also intrinsically lead to poor electrochemical activity and thus low active material utilization. And the volume change arising from the conversion between S and Li2S is also a concern, in terms of cycle stability. To solve the aforementioned problems, our group has designed multi-functional sulfur matrix for a cathode and hierarchical interlayers for novel batteries configurations based on nano-structured carbon and metal oxides. Specifically, a polygonal nano carbon particles derived from a microporous zeolitic imidazolate framework (ZIF-8) was chosen as S-matrix, which was further wrapped by ultra-thin graphene to form a sandwich-like architecture. By taking advantages of the synergistic effect of hybrid conductive carbon and half-closed nano-scale design, stable cycle performance was achieved. To further advance the development of Li-S for practical application, we propose a conceptual design of a bio-inspired polysulfides brush by integration of polar metal oxide and inter-connected conductive frameworks. After the incorporation of this bio-inspired interlayer, excellent cycle and rate performance have been achieved for cathode with a high S loading. We strongly believe the design of chemi-functional interlayers with a brush-like nano-architecture opens a new direction for advancing high-performance Li-S batteries.