Issue 9, 2019

Highly reversible potassium-ion intercalation in tungsten disulfide

Abstract

Rechargeable potassium-ion batteries (PIBs) show promise beyond Li-ion technology in large-scale electrical-energy storage due to the abundance and low cost of potassium resources. However, the intercalation of large-size K+ generally results in irreversible structural degradation and short lifespan to the hosts, representing a major obstacle. Here, we report a new electrochemical K+-intercalation host, tungsten disulfide (WS2), which can store 0.62 K+ per formula unit with a reversible capacity of 67 mA h gāˆ’1 and well-defined voltage plateaus at an intrinsically safe average operation potential of 0.72 V versus K/K+. In situ X-ray diffraction and ex situ electron microscopy revealed the underlying intercalation mechanism, a relatively small cell volume change (37.81%), and high reversibility of this new battery chemistry. Such characteristics impart WS2 with ultrahigh structural stability and a long lifespan, regardless of deep or fast charging. WS2 achieved record-high cyclability among chalcogenides up to 600 cycles with 89.2% capacity retention at 0.3C, and over 1000 cycles with 96.3% capacity retention and an extraordinary average Coulombic efficiency of 99.90% at 2.2C. This intercalation electrochemistry may open up new opportunities for the design of long-cycle-life and high-safety PIBs.

Graphical abstract: Highly reversible potassium-ion intercalation in tungsten disulfide

Supplementary files

Article information

Article type
Edge Article
Submitted
30 Sep 2018
Accepted
24 Dec 2018
First published
27 Dec 2018
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY-NC license

Chem. Sci., 2019,10, 2604-2612

Highly reversible potassium-ion intercalation in tungsten disulfide

R. Zhang, J. Bao, Y. Pan and C. Sun, Chem. Sci., 2019, 10, 2604 DOI: 10.1039/C8SC04350G

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