Ultrathin Cobalt-Based Prussian Blue Analogue Nanosheet-Assembled Nanoboxes Interpenetrated with Carbon Nanotubes as a Fast Electron/Potassium-Ion Conductor for Superior Potassium Storage

Abstract

Rechargeable potassium-ion batteries (PIBs) are regarded as potential substitutes for industrial lithium-ion batteries in large scale energy storage systems due to the world’s abundant potassium supplies. Althogh cobalt hexacyanocobaltate (CoHCC) exhibits broad potential as a PIB anode material, its performance is currently unsatisfactory. Herein, novel 5 nm scale ultrathin CoHCC nanosheet-assembled nanoboxes with interspersed carbon nanotubes (CNTs/CoHCC nanoboxes) are fabricated to realize a highly reactive PIB anode. The ultrathin CoHCC layers substantially accelerate electron conduction and provide numerous active sites, while the connected CNTs provide fast axial electron transport. Consequently, the optimized anode exhibits a remarkable discharge capacity of 580.9 mAh g–1 at 0.1 A g–1 and long-term stability with 71.3% retention over 1000 cycles. In situ and ex situ characterizations and density functional theory calculations are further employed to elucidate the K+ storage process and the reason for the enhanced performance of the CNTs/CoHCC nanoboxes.

Solvation Structure of Methanol-in-Salt Electrolyte Revealed by Small-Angle X-ray Scattering and Simulations

“…Considerable advantages were found for water-in-salt electrolytes (WISE) compared with the commercial organic electrolytes after introduced by Suo and his colleagues: nonflammable, nonvolatile, low toxicity, and wider electrochemical window. − Following this premier work, a fair amount of studies with multiple advanced techniques, such as Raman spectroscopy and infrared spectroscopy (IR), have been reported to explore the solvation structure of the WISE. − The anion coordination mode for imide-based electrolyte was commonly investigated by deconvoluting the Raman peak (S–N–S bending vibration) into three bands, which correspond to solvent-separated ion pair (SSIP), contact ion pair (CIP), and aggregate (AGG), respectively. − By analyzing the shift of infrared peaks caused by the vibration of the hydrogen–oxygen bond or deuterium-oxygen bond, the bulk-like and ion-bound water were found to coexist in the system and serve different roles as a medium for lithium ion transport and a lubricant, respectively. ,,, …”

Copper-Decorated Titanium Electrodes: Impact of Surface Modifications of Substrate on the Morphology and Electrochemical Performance

“…This also implies slower deterioration of the electrode materials and improved selectivity in the reactions with electrogeneration of fewer unwanted byproducts. For these reasons, many ongoing studies focus on the development of cathodic processes especially for environmental protection, , and the advancement of cathode materials for CO 2 and nitrate electroreduction as well as for battery applications. , …”

Tunable Interfacial Electric Field‐Mediated Cobalt‐Doped FeSe/Fe3Se4 Heterostructure for High‐Efficiency Potassium Storage

“…Therefore, numerous studies focus on improving electrochemical performance through advanced strategies such as morphology design, defect introduction, and heterostructure construction. [12][13][14][15][16][17][18] However, rational utilization of these strategies to improve potassium storage performance remains an intractable conundrum.…”