In situ polyaniline coating of Prussian blue as cathode material for sodium-ion battery
Creators: name: luo, yu
name: Yang, LingXiao
name: liu, Qing
name: Yan, Youwei
Publisher: name: Zenodo
Year: 2021
Subjects: ball-mill
prussian blue
nano particle
cube
in situ coating
sodium ion battery

description: Prussian blue has potential for use as a sodium anode material owing to its high working potential and cube frame structure. Instead of the traditional co-precipitation method, we used a two-step method to synthesize Prussian blue, with ascorbic acid as the ball-milling additive. The obtained sample exhibited a superior rate specific capability (113.3 mAh g-1 at 20 C) and adequate cycling stability when cycled at 1 C with a specific capacity retention of 84.8% after 100 cycles. In order to enhance the cycling performance of the sample, an in situ PANI coating strategy was employed in which aniline was added into the electrolyte and polymerized under electrochemical conditions. The electrode then exhibited a high specific capacity retention of 62.7% after 500 cycles, which is significantly higher than that of the former sample (40.1% after 500 cycling). This development will help guide future research on sodium-ion batteries.
description: Funding provided by: National Natural Science Foundation of China<br>Crossref Funder Registry ID: http://dx.doi.org/10.13039/501100001809<br>Award Number: Grant No. 51002054
description: <b>Materials</b> Ferrous sulfate, sodium ferro-cyanide, aniline, ascorbic acid and anhydrous ethanol solution was purchased from Aladdin company. DI water was used in all the synthesis process. <b>Characterizations</b> The X-ray diffraction (XRD) pattern was measured by PANalytical B.V. with a Cu Kα radiation test ranging from 10° to 80°. Scanning electron microscopy (SEM) images were obtained with a Nova NanoSEM 450, in order to fix the samples on the observe table, all the samples pasted with conductive carbon tape as base. Raman spectrometry was tested for with a LabRAM HR800, 532 light source ranging from 1500 to 2500 cm<sup>-1</sup>. The elemental analysis (EA) was carried via a Vario Micro cube for detecting C and N content. The inductively coupled plasma mass spectrometry (ICP-MS) was carried out via Prodigy Plus for detecting Na and Fe contents. The thermogravimetric analyses (TGA) were carried out with a Diamond TG at a rate of 10 °C/min in N2. The X-ray photoelectron spectroscopy was performed with an AXIS-ULTRA DLD-600W from 695 to 745 eV. The transmission electron microscopy (TEM) images were obtained via a Talos F200X operated at 200 kV. <b>Electrochemical measurements</b> The cathode was composed of Prussian blue: Ketjen black: Super P: Polyvinylidene fluoride (PVDF) at a weight ratio of 7:1:1:1 on Al foil. The electrode was dried in a vacuum oven at 120 °C for 10 hours. The half cell was assembled in an Ar-filled glove box (moisture and oxygen contents were less than 1 ppm). The electrolyte was composed of NaClO<sub>4</sub> dissolved in 1:1 diethyl carbonate/ethylene carbonate containing 5 wt. % fluoroethylene carbonate. Whatman glass fiber was used as the separator, and Na metal was used as the counter electrode. The electrochemical charge/discharge tests were conducted between 2.0 and 4.0 V at room temperature with a Land CT2001 battery tester (Land Electronics, China). Cyclic voltammetry measurements and electrochemical impedance spectroscopy tests were carried out by the electrochemical workstation (CHI760E, China).