Dataset analysis on Cu9S5 material structure and its electrochemical behavior as anode for sodium-ion batteries

The data presented in this data article are related to the research article entitled “Facile Synthetic Strategy to Uniform Cu9S5 Embedded into Carbon: A Novel Anode for Sodium-Ion Batteries” (Jing et al., 2018) [1]. The related experiment details of pure Cu9S5 has been stated. The structure data of pure Cu9S5 and the electrochemical performance for sodium-ion batteries are described.


a b s t r a c t
The data presented in this data article are related to the research article entitled "Facile Synthetic Strategy to Uniform Cu 9 S 5 Embedded into Carbon: A Novel Anode for Sodium-Ion Batteries"   [1]. The related experiment details of pure Cu 9 S 5 has been stated. The structure data of pure Cu 9 S 5 and the electrochemical performance for sodium-ion batteries are described.
& 2018 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Subject area
Chemistry More specific subject area Sodium-ion batteries Type of data Figure  How data

Value of the data
Detailed experimental data might be used in the development of further experiments in a particular area.
The summary of material properties can be utilized to compare together and easily accessed from the various applications.
The CV curves could be used for more scientific analysis of various metal sulfide as anode for Na-ion batteries.

Data
In this data article, the detailed experimental method of pure Cu 9 S 5 sample has been presented. The X-ray diffraction (XRD) pattern and Cyclic voltammetry (CV) files of as-prepared sample shown in Fig. 1, which is utilized to analysis the electrochemical performance of as-prepared material as anode for sodium-ion batteries.

Experimental design, materials, and methods
An ethylenediamine-assisted hydrothermal method has been utilized to prepare pure Cu 9 S 5 nanomaterial, according to previous report [2]. The detailed experimental design is as follows. Firstly, 6.0 mL of anhydrous ethylenediamine was dissolved in 24.0 mL deionized water. 1.5 mmol of Cu (NO 3 ) 2 Á 6H 2 O was dissolved the above solution to form a blue solution with ultrasonic dispersion for 10 minutes. And then, 1.5 mmol of thiourea was introduced to the solution in batches, while the above solution is in the process of magnetic stirring. After 30 min, the color of mixture become deep blue. Then, this mixture system was transferred into a 50 mL Teflon-lined stainless steel autoclave and treated at 120°C for 2 h. Furthermore, black precipitates were deposited on autoclave bottom after the temperature dropping down to room temperature naturally. The pale upper clear liquid was poured out. Then, the black precipitates were washed several times utilizing absolute ethanol and distilled water with (1:1 of the volume ratio). Finally, the products were further dried at 80°C for 24 h, and the pure Cu 9 S 5 was obtained.
X-ray diffraction (XRD) has been utilized to investigate the crystalline structure of pure Cu 9 S 5 . The detailed test parameters are based on Ref. [1]. Cyclic voltammetry (CV) tests of pure Cu 9 S 5 has been measured on electrochemical working station (CHI 660B) through assembled CR2025 coin cells utilizing sodium foil as counter and reference electrode, according to previous report [1]. Furthermore, the CV profiles of Cu 9 S 5 were tested with the potential range from 0.01 to 3.0 V (vs Na/Na þ ) at 0.2 mV s À 1 , which is shown in Fig. 1b. In the first cathodic scan, several oxidation peaks take place from 0.2 to 2.0 V, which is mainly attributed to the oxidation reactions of Cu 9 S 5 , the insertion process of Na þ into electrode material, and the formation of solid electrolyte interphase (SEI) [1,3,4]. During the following anodic scanning, two major peaks at 1.65 and 2.12 V represent the electrochemical reaction from Cu and Na 2 S to Na α Cu β S γ and further changed into Cu 9 S 5 [5]. These obvious redox peaks of pure Cu 9 S 5 are present, illustrating the pure Cu 9 S 5 active material mainly presents conversion reaction in the sodiation/desodiation process. Additionally, the microstructure analysis indicates that Cu 9 S 5 electrode material could also exhibit little insertion/extraction mechanism like other metal sulfides [6,7].