Metal–Organic Framework-Derived Magnesium Oxide@Carbon Interlayer for Stable Lithium–Sulfur Batteries

Abstract

Lithium sulfur (Li–S) batteries represent a promising future battery technology. However, the low electrical conductivity of solid-state sulfur species (S, Li2S2, and Li2S) and the polysulfide shuttle effect deteriorate their practical capacity and cycling retention. Herein, we present an interlayer composed of magnesium oxide (MgO) nanoparticles and carbon matrix for the Li–S batteries. In the composite, MgO can capture dissolved polysulfides that diffuse to the carbon matrix along the oxide surface for further reduction reactions. As a novel precursor to produce the composite structure, a Mg metal–organic-framework, Mg-MOF-74, is adopted and synthesized on a free-standing carbon paper (MOF/C-paper). Through pyrolysis, Mg-MOF-74 is converted into highly porous carbon containing uniformly distributed MgO nanoparticles (MgO@C/C-paper). The Li–S cells assembled with MgO@C/C-paper and C-paper interlayer show significantly higher initial capacities (980 and 898 mAh g–1, respectively) than the interlayer-free cell (729 mAh g–1) owing to the conductive interlayers. After 200 cycles at 0.2 C, the MgO@C/C-paper cell presents a cycle retention (78.3%) superior to that of the C-paper cell (76.5%). With a higher sulfur loading of 3.3 mg cm–2, the MgO@C/C-paper cell exhibits an even higher capacity retention (80.1%) than the C-paper cell (54.6%) after 100 cycles. The excellent cycle stability of the MgO@C/C-paper cell over the C-paper cell demonstrates that the unique structure of the MOF-derived MgO@C is highly effective in anchoring and reutilizing dissolved polysulfides.

Rare‐Earth Doped Configurational Entropy Stabilized High Entropy Spinel Oxide as an Efficient Anchoring/Catalyst Functional Interlayer for High‐Performance Lithium‐Sulfur Battery

“…had reported that single metal oxide MnO 2 nanosheets as a functional interlayer exhibited capacity retention of only 93 % after 100 cycles at a low 0.2 C rate with an even lower sulfur loading of 0.7 mg cm −2 while Gope and Bhattacharyya [62] employed NiO as an interlayer which showed stable cycling stability only up to 100 cycles. Likewise, Kang et al [63] . reported on an MgO interlayer in carbon matrix which exhibited capacity retention of only 78.3 % after 200 cycles at 0.2 C rate.…”

“…Nazar et al [61] had reported that single metal oxide MnO 2 nanosheets as a functional interlayer exhibited capacity retention of only 93 % after 100 cycles at a low 0.2 C rate with an even lower sulfur loading of 0.7 mg cm À 2 while Gope and Bhattacharyya [62] employed NiO as an interlayer which showed stable cycling stability only up to 100 cycles. Likewise, Kang et al [63] reported on an MgO interlayer in carbon matrix which exhibited capacity retention of only 78.3 % after 200 cycles at 0.2 C rate. On the other hand, the TM-RE HEO interlayer in the present study exhibits long-term cycling stability at 0.5 C rate with as low a capacity decay of 0.08 % per cycle after 300 cycles at a comparatively higher sulfur loading of 1.5 mg cm À 2 .…”

Ti3C2Tx nanosheet@Cu/Fe-MOF separators for high-performance lithium–sulfur batteries: an experimental and density functional theory study

“…The contribution of MOFs improves the active materials' utilization and the electrochemical performance by enhancing the trapping of polysulfides through chemisorption. [18][19][20] However, their poor electrical conductivity may limit their wide applications in Li-S batteries.…”

In Situ Generation of Co-Decorated Carbon Nanotubes by Zeolitic Imidazolate Frameworks to Facilitate High-Performance Lithium–Sulfur Batteries

“…Therefore, ZIFs have been widely studied in the oxygen reduction/evolution reaction, hydrogen evolution reaction, lithium batteries, etc. 20,21 However, the specific surface area of ZIF-derived materials is generally small, and the performance of metal active sites is limited. 22,23 Herein, the cubic form of ZIF-67 is synthesized.…”