TY - JOUR A1 - Xie, Dongjiu A1 - Mei, Shilin A1 - Xu, Yaolin A1 - Quan, Ting A1 - Haerk, Eneli A1 - Kochovski, Zdravko A1 - Lu, Yan T1 - Efficient sulfur host based on yolk-shell iron oxide/sulfide-carbon nanospindles for lithium-sulfur batteries JF - ChemSusChem : chemistry, sustainability, energy, materials N2 - Numerous nanostructured materials have been reported as efficient sulfur hosts to suppress the problematic "shuttling" of lithium polysulfides (LiPSs) in lithium-sulfur (Li-S) batteries. However, direct comparison of these materials in their efficiency of suppressing LiPSs shuttling is challenging, owing to the structural and morphological differences between individual materials. This study introduces a simple route to synthesize a series of sulfur host materials with the same yolk-shell nanospindle morphology but tunable compositions (Fe3O4, FeS, or FeS2), which allows for a systematic investigation into the specific effect of chemical composition on the electrochemical performances of Li-S batteries. Among them, the S/FeS2-C electrode exhibits the best performance and delivers an initial capacity of 877.6 mAh g(-1) at 0.5 C with a retention ratio of 86.7 % after 350 cycles. This approach can also be extended to the optimization of materials for other functionalities and applications. KW - batteries KW - electrode materials KW - lithium sulfides KW - yolk-shell KW - nanostructures Y1 - 2021 U6 - https://doi.org/10.1002/cssc.202002731 SN - 1864-5631 SN - 1864-564X VL - 14 IS - 5 SP - 1404 EP - 1413 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Quan, Ting A1 - Haerk, Eneli A1 - Xu, Yaolin A1 - Ahmet, Ibbi A1 - Höhn, Christian A1 - Mei, Shilin A1 - Lu, Yan T1 - Unveiling the formation of solid electrolyte interphase and its temperature dependence in "Water-in-Salt" supercapacitors JF - ACS applied materials & interfaces N2 - "Water-in-salt" (WIS) electrolytes have emerged as an excellent superconcentrated ionic medium for high-power energy storage systems such as supercapacitors due to their extended working potential compared to the conventional dilute aqueous electrolyte. In this work, we have investigated the performance of WIS supercapacitors using hollow carbon nanoplates as electrodes and compared it to that based on the conventional "salt-in-water" electrolytes. Moreover, the potentiostatic electrochemical impedance spectroscopy has been employed to provide an insightful look into the charge transport properties, which also, for the first time, reveals the formation of a solid-electrolyte interphase (SEI and their temperature-dependent impedance for charge transfer and adsorption. Furthermore, the effect of temperature on the electrochemical performance of the WIS supercapacitors in the temperature range from 15 to 60 degrees C has been studied, which presents a gravimetric capacitance of 128 F g(-1) and a volumetric capacitance of 197.12 F cm(-3) at 55 degrees C compared to 87.5 F g(-1) and 134.75 F cm(-3) at 15 degrees C. The in-depth understanding about the formation of SEI layer and the electrochemical performance at different temperatures for WIS supercapacitors will assist the efforts toward designing better aqueous electrolytes for supercapacitors. KW - "water-in-salt" KW - supercapacitor KW - solid electrolyte interphase KW - electrochemical impedance spectroscopy KW - temperature effect Y1 - 2021 U6 - https://doi.org/10.1021/acsami.0c19506 SN - 1944-8244 SN - 1944-8252 VL - 13 IS - 3 SP - 3979 EP - 3990 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Xie, Dongjiu A1 - Jouini, Oumeima A1 - Mei, Shilin A1 - Quan, Ting A1 - Xu, Yaolin A1 - Kochovski, Zdravko A1 - Lu, Yan T1 - Spherical polyelectrolyte brushes templated hollow C@MnO nanospheres as sulfur host materials for Li-S batteries JF - ChemNanoMat : Chemistry of Nanomaterials for Energy, Biology and More N2 - Li-S battery has been considered as the next-generation energy storage device, which still suffers from the shuttle effect of lithium polysulfides (LiPSs). In this work, mesoporous hollow carbon-coated MnO nanospheres (C@MnO) have been designed and synthesized using spherical polyelectrolyte brushes (SPB) as template, KMnO4 as MnO precursor, and polydopamine as carbon source to improve the electrochemical performance of Li-S battery. The hollow C@MnO nanospheres enable the combination of physical confinement and chemical adsorption of the LiPSs. The thin carbon coating layer can provide good electrical conductivity and additional physical confinement to polysulfides. Moreover, the encapsulated MnO inside the carbon shell exhibits strong chemical adsorption to polysulfides. The constructed C@MnO/S cathode shows the discharge capacity of 1026 mAh g(-1) at 0.1 C with 79% capacity retention after 80 cycles. The synthesized hollow C@MnO nanoparticles can work as highly efficient sulfur host materials, providing an effective solution to suppress the shuttle effect in Li-S battery. KW - hollow nanospheres KW - lithium-sulfur battery KW - manganese monoxide KW - sperical KW - polyelectrolyte brushes Y1 - 2022 U6 - https://doi.org/10.1002/cnma.202100455 SN - 2199-692X VL - 8 IS - 4 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Mei, Shilin A1 - Siebert, Andreas A1 - Xu, Yaolin A1 - Quan, Ting A1 - Garcia-Diez, Raul A1 - Bär, Marcus A1 - Härtel, Paul A1 - Abendroth, Thomas A1 - Dörfler, Susanne A1 - Kaskel, Stefan A1 - Lu, Yan T1 - Large-Scale Synthesis of Nanostructured Carbon-Ti4O7 Hollow Particles as Efficient Sulfur Host Materials for Multilayer Lithium-Sulfur Pouch Cells JF - Batteries & supercaps N2 - Applications of advanced cathode materials with well-designed chemical components and/or optimized nanostructures promoting the sulfur redox kinetics and suppressing the shuttle effect of polysulfides are highly valued. However, in the case of actual lithium-sulfur (Li-S) batteries under practical working conditions, one long-term obstacle still exists, which is mainly due to the difficulties in massive synthesis of such nanomaterials with low cost and ease of control on the nanostructure. Herein, we develop a facile synthesis of carbon coated Ti4O7 hollow nanoparticles (Ti4O7) using spherical polymer electrolyte brush as soft template, which is scalable via utilizing a minipilot reactor. The C Ti4O7 hollow nanoparticles provide strong chemical adsorption to polysulfides through the large polar surface and additional physical confinement by rich micro- & mesopores and have successfully been employed as an efficient sulfur host for multilayer pouch cells. Besides, the sluggish kinetics of the sulfur and lithium sulfide redox mechanism can be improved by the highly conductive Ti4O7 via catalyzation of the conversion of polysulfides. Consequently, the C-Ti4O7 based pouch cell endows a high discharge capacity of 1003 mAhg(-1) at 0.05 C, a high-capacity retention of 83.7% after 100 cycles at 0.1 C, and a high Coulombic efficiency of 97.5% at the 100th cycle. This work proposes an effective approach to transfer the synthesis of hollow Ti4O7 nanoparticles from lab- to large-scale production, paving the way to explore a wide range of advanced nanomaterials for multilayer Li-S pouch cells. KW - lithium-sulfur batteries KW - pouch cell KW - spherical polyelectrolyte brushes (SPB) KW - Ti4O7 Y1 - 2022 U6 - https://doi.org/10.1002/batt.202100398 SN - 2566-6223 VL - 5 IS - 6 PB - Wiley-VCH CY - Weinheim ER -