ฉันรักแปล2. Experimental
2.1. Electrode preparation and test
The commercial ErCl36H2O salts were directly used without further
purification. The supercapacitor electrodes were prepared by
mixing 70 wt% ErCl36H2O salts, 20 wt% carbon black, and 10 wt%
polyvinylidene fluoride (PVDF) and dissolving in N-methyl-2-pyrrolidone
(NMP) solution. Briefly, the resulting slurry was spread
on nickel foam current collector with an area of 1 1 cm2. The electrodes
were dried at 80 C for 24 h, and finally pressed at 10 MPa and
served as working electrode. The loading of each electrode is 4 to
5 mg. Cyclic voltammetry (CV), and galvanostatic charge–discharge
measurements were obtained using an electrochemical workstation
(CHI 660D) at designed potential range, scan rate and current density.
All electrochemical experiments were carried out using a classical
three-electrode configuration in 2 M KOH electrolytes. The
saturated calomel electrode (SCE) was used as the reference electrode,
and Pt wire electrode as a counter electrode.
2.2. Characterization
To observe surface morphologies of ErCl36H2O salt electrodes
before and after electrochemical tests, scanning electron microscope
was performed by a field-emission scanning electron microscope
(FESEM, Hitachi-S4800) at acceleration voltage of 10 kV.
Chemical compositions of integrated electrodes were recorded
using powder X-ray diffractometer (XRD, Rigaku-D/max 2500 V).
3. Results and discussion
Scheme 1 shows the fabrication process of ErCl3 electrode. ErCl3
electrodes were prepared by pasting a slurry mixture of commercial
ErCl36H2O salts, carbon black, and poly(vinylidene fluoride)
(PVDF) on a Ni foam, which did not need the additional complex
synthesis procedures for active materials. The present results challenge
the view that the synthesis of advanced materials is the key
Scheme 1. Schematic drawing shows in situ fabrication of ErCl3 pseudocapacitor.
Firstly, the electrode was fabricated with the use of commercial ErCl36H2O salts by
slurry-coating manufacturing. Then, ErOOH colloids were in situ crystallized by
electric-field assisted chemical coprecipitation, and subsequently integrated into
practical electrode structures. At the same time, pseudocapacitive Faradaic reaction
was occurred at the same electrode. In situ crystallized ErOOH colloids can enhance
electrochemical utilization of active Er cations.
0 50 100 150 200 250 300 350
-0.1
0.0
0.1
0.2
0.3
0.4
3A/g
5A/g
7A/g
10A/g
15A/g
20A/g
30A/g
Potential (V vs. SCE)
Time (s)
0 5 10 15 20 25 30
0
500
1000
1500
Specific capacitance (F/g)
Current density (A/g)
Weight of Er3+ ion
Weight of ErCl3 salt
a
b
Fig. 1. Electrochemical performance of ErCl3 pseudocapacitor. (a) The charge/
discharge curves (time versus potential) measured at various current densities and
a potential range of 0.55 V. (b) Specific capacitance of inorganic ErCl3 salt electrode
versus discharge current density at potential window of 0.55 V based on the weight
of ErCl36H2O salt and Er3+ ion. All data are taken in a 2 M KOH electrolyte at room
temperature