Shielding unfavorable interaction by oxygen-mediated interlayer chemical bonding enables high-capacity and stable MoS2 cathode

Abstract

Molybdenum disulfide (MoS2) as cathodes for aqueous zinc-ion batteries (AZIBs) typically undergoes sluggish kinetics and irreversible structure distortion because of the strong interaction between intensely electronegative sulfur and intercalated Zn2+, especially for thick electrodes. Herein, we propose a new oxygen-mediated interlayer chemical bonding strategy to achieve high-performance MoS2 cathode in thick electrode (5–15 mg cm−2). The oxygen-mediated interlayer chemical bonding is facilely formed by intercalating oxygen-rich β-cyclodextrin into MoS2 nanosheets (denoted as MoS2-β-CD), which not only expands the interlayer spacing (from 6.4 to 9.6 Å) but also effectively weakens the electrostatic interaction between Zn2+ and host frameworks, endowing it with fast electron/ion transport and robust structural stability. Consequently, even with 10 mg cm−2 loading, the MoS2-β-CD cathode delivers an impressive specific capacity of 228.0 mA h g−1 (2.3 mA h cm−2) at 4 mA cm−2, superior to most advanced MoS2-based electrodes. Additionally, the MoS2-β-CD electrode also possesses significantly enhanced durability (85.3 % vs. 28.6 % capacity retention after 5000 cycles). This work provides unique inspiration for rational design of AZIB cathodes for practical applications.