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- Agostini, Marco, 1987, et al.
(författare)
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Designing Highly Conductive Functional Groups Improving Guest-Host Interactions in Li/S Batteries
- 2020
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 16:2
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Tidskriftsartikel (refereegranskat)abstract
- Li-sulfur batteries are of great interest due to their potential to surpass the energy densities of other battery types, but the low electronic conductivity of both sulfur and its discharge products requires the use of a conductive host material. The most common is the use of different porous carbons which normally are hydrophobic and hardly retain the polar discharge products of the Li/S reaction, such as Li2S and lithium polysulfides (LiPs), at the working electrode. Functionalized hosts have been proposed as a strategy to improve LiPs interactions, including the use of heteroatom doping, organic frameworks, metals, metal oxides, sulfide particles, and conductive polymers. Despite demonstrating an improved cycle life, the functionalized structures often have an intrinsic limitation related to a low electronic conductivity resulting in slow kinetics and poor rate capability of Li/S cells. Herein, recent research trends aimed at designing sulfur electrodes with highly conductive functional groups on nanostructured hosts surface are reviewed. The main concepts, key developments, and parameters for building 3D hosts architectures that enable fast charge rates and long cycle life at high sulfur loadings are discussed.
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| 2. |
- Sun, Jinhua, 1987, et al.
(författare)
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Critical Role of Functional Groups Containing N, S, and O on Graphene Surface for Stable and Fast Charging Li-S Batteries
- 2021
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 17:17
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Tidskriftsartikel (refereegranskat)abstract
- Lithium‐sulfur (Li‐S) batteries are considered one of the most promising energy storage technologies, possibly replacing the state‐of‐the‐art lithium‐ion (Li‐ion) batteries owing to their high energy density, low cost, and eco‐compatibility. However, the migration of high‐order lithium polysulfides (LiPs) to the lithium surface and the sluggish electrochemical kinetics pose challenges to their commercialization. The interactions between the cathode and LiPs can be enhanced by the doping of the carbon host with heteroatoms, however with relatively low doping content (<10%) in the bulk of the carbon, which can hardly interact with LiPs at the host surface. In this study, the grafting of versatile functional groups with designable properties (e.g., catalytic effects) directly on the surface of the carbon host is proposed to enhance interactions with LiPs. As model systems, benzene groups containing N/O and S/O atoms are vertically grafted and uniformly distributed on the surface of expanded reduced graphene oxide, fostering a stable interface between the cathode and LiPs. The combination of experiments and density functional theory calculations demonstrate improvements in chemical interactions between graphene and LiPs, with an enhancement in the electrochemical kinetics, power, and energy densities.
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