Unlock the Potassium Storage Behavior of Single‐Phased Tungsten Selenide Nanorods via Large Cation Insertion. Issue 5 (26th December 2022)

• Record Type: Journal Article
• Authors: Zhao, Zhongchen; Xu, Tian; Yu, Xuebin
• Is Part Of: Advanced materials. Volume 35:Issue 5(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-12-26
• Subjects: capacity deterioration mechanism -- K + pre‐intercalated WSe 2 -- potassium‐ion batteries -- potassium‐ion hybrid capacitor -- ultrahigh stability; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202208096
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Metal chalcogenide anodes with a layered structure have been regarded as potential K‐based electrochemical energy storage devices with high energy density for large‐scale energy storage applications. However, their development is impeded by the slow K‐ion transport kinetics and poor structural stability. In this work, the energy‐storage behavior is investigated first and decisively associated them with the capacity‐degradation of the promising layer‐structured WSe2 from an integrated chemical and physical point of view. Then, a single‐phased WSe2 with pre‐intercalated high K content (SP‐Kx WSe2 ) is designed to overcome the capacity‐degradation issue fundamentally. Theoretical calculations clarify the beneficial effect of K‐ions inside the interlayer of WSe2 on boosting its electrochemical performance, including increasing the electronic conductivity, promoting the K‐ion diffusivity, and improving the structural stability. The novel design enables the K‐ions pre‐intercalated WSe2 anode material to exhibit a high reversible specific capacity of 211 mAh g −1 at 5 A g −1 and superior cycling stability (89.3% capacity retention after 5000 cycles at 1 A g −1 ). Especially, the K‐ion hybrid capacitor, assembled from the anode of SP‐Kx WSe2 and the cathode of porous activated carbon, delivers superior energy‐density up to 175 Wh kg −1, high power‐density as well as exceptional cycling stability. Abstract : Here, in/ex situ experiments and theoretical calculations are performed to investigate the role of tunnel cations in governing the charge storage performances of electrodes by focusing on K‐ions in layer‐structured WSe2 . It clearly reveals that the pre‐intercalated K‐ions inside interlayers of WSe2 increases the electronic conductivity, and improves K‐ion diffusivity, having fast kinetics response during the K‐ion (de)insertion.