Conversion Synthesis of Self-Standing Potassium Zinc Hexacyanoferrate Arrays as Cathodes for High-Voltage Flexible Aqueous Rechargeable Sodium-Ion Batteries

Bing He; Ping Man; Qichong Zhang; Chao Wang; Zhenyu Zhou; Chaowei Li; Lei Wei; Yagang Yao

doi:10.1002/smll.201905115

Conversion Synthesis of Self-Standing Potassium Zinc Hexacyanoferrate Arrays as Cathodes for High-Voltage Flexible Aqueous Rechargeable Sodium-Ion Batteries

Small. 2019 Dec;15(52):e1905115. doi: 10.1002/smll.201905115. Epub 2019 Nov 26.

Authors

Bing He^{1

2

3}, Ping Man^{1

2}, Qichong Zhang⁴, Chao Wang^{1

2}, Zhenyu Zhou^{1

2}, Chaowei Li^{1

2}, Lei Wei⁴, Yagang Yao^{1

3

5}

Affiliations

¹ Division of Advanced Nanomaterials, Key Laboratory of Nanodevices and Applications, Joint Key Laboratory of Functional Nanomaterials and Devices, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China.
² School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei, 230026, China.
³ Division of Nanomaterials, Suzhou Institute of Nano-Tech and Nano-Bionics, Nanchang, Chinese Academy of Sciences, Nanchang, 330200, China.
⁴ School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.
⁵ National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.

PMID: 31769612
DOI: 10.1002/smll.201905115

Abstract

Prussian blue analogs exhibit great promise for applications in aqueous rechargeable sodium-ion batteries (ARSIBs) due to their unique open framework and well-defined discharge voltage plateau. However, traditional coprecipitation methods cannot prepare self-standing electrodes to meet the needs of wearable energy storage devices. In this work, a water bath method is reported to grow microcube-like K₂ Zn₃ (Fe(CN)₆ )₂ ·9H₂ O on carbon cloth (CC) using Zn nanosheet arrays as the zinc source and reducing agent, directly serving as a self-standing cathode. Benefiting from fast ion diffusion and high conductivity, the cathode delivers a high areal capacity of 0.76 mAh cm^-2 at 0.5 mA cm^-2 and excellent capacity retention of 57.9% as the current density increases to 20 mA cm^-2 . By coupling with NaTi₂ (PO₄ )₃ grown on CC as an anode, a quasi-solid-state flexible ARSIB with a high output voltage plateau of 1.6 V is successfully assembled, exhibiting a superior areal capacity of 0.56 mAh cm^-2 and energy density of 0.92 mWh cm^-2 . In particular, the device shows admirable mechanical flexibility, maintaining 90.3% of initial capacity after 3000 bending cycles. This work is anticipated to open a new avenue for the rational design of self-standing electrodes used in high-voltage flexible ARSIBs.

Keywords: aqueous sodium-ion batteries; high-voltage; mechanical flexibility; potassium zinc hexacyanoferrates; self-standing electrodes.

Abstract

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