Pseudocapacitive Charge Storage in Thick Composite MoS₂ Nanocrystal-Based Electrodes

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• 作者：John B. Cook ; Hyung-Seok Kim ; Terri C. Lin ; Chun-Han Lai ; Bruce Dunn and Sarah H. Tolbert
• 刊名：Advanced Energy Materials
• 出版年：2017
• 出版时间：January 25, 2017
• 年：2017
• 卷：7
• 期：2
• 全文大小：3877K
• ISSN：1614-6840

文摘

A synthesis methodology is demonstrated to produce MoS₂ nanoparticles with an expanded atomic lamellar structure that are ideal for Faradaic-based capacitive charge storage. While much of the work on MoS₂ focuses on the high capacity conversion reaction, that process is prone to poor reversibility. The pseudocapacitive intercalation-based charge storage reaction of MoS₂ is investigated, which is extremely fast and highly reversible. A major challenge in the field of pseudocapacitive-based energy storage is the development of thick electrodes from nanostructured materials that can sustain the fast inherent kinetics of the active nanocrystalline material. Here a composite electrode comprised of a poly(acrylic acid) binder, carbon fibers, and carbon black additives is utilized. These electrodes deliver a specific capacity of 90 mAh g⁻¹ in less than 20 s and can be cycled 3000 times while retaining over 80% of the original capacity. Quantitative kinetic analysis indicates that over 80% of the charge storage in these MoS₂ nanocrystals is pseudocapacitive. Asymmetric full cell devices utilizing a MoS₂ nanocrystal-based electrode and an activated carbon electrode achieve a maximum power density of 5.3 kW kg⁻¹ (with 6 Wh kg⁻¹ energy density) and a maximum energy density of 37 Wh kg⁻¹ (with 74 W kg⁻¹power density).