Correspondence should be addressed to Prof. I.T. Kim and Prof. J. Hur

Transcription

1 Supporting information Enabling high performance calcium-ion batteries from Prussian blue and metal-organic compound materials Thuan Ngoc Vo, a Jaehyun Hur, a,** and Il Tae Kim a,* a Department of Chemical and Biological Engineering, Gachon University, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea * Correspondence should be addressed to Prof. I.T. Kim and Prof. J. Hur S1

2 Experimental Synthesis of Prussian Blue Firstly, 5.28 g of K 4 Fe(CN) 6.3H 2 O was dissolved in 125 ml of DI water to form a clear solution A. 125 ml of solution containing 2.52 g Fe(NO 3 ) 3.9H 2 O was dropped into solution A at 60 o C for 2 hours to obtain a dark blue mixture. The precipitation was isolated via centrifugation at rpm and washed with DI water/ ethanol/ acetone several times. The Prussian blue was dried at 70 o C under vacuum overnight. Synthesis of Ni-based MOCs (Nibdc, NibdcNH2, Ni4ABA) 1.66 g of 1,4-benzenedicarboxylic acid was reacted with 0.80 g of NaOH in 100 ml DI water at 90 o C for 6 hours to obtain a clear solution. Later, 1.54 g of NiCl 2 in 50 ml DI water was dropped into the aforementioned solution at 80 o C and left overnight. The obtained precipitated Nibdc was extracted via centrifugation, washed with DI water before drying at 70 o C under vacuum overnight. For the preparation of NibdcNH2 and Ni4ABA, 10 mmol of 2-amino-1,4-benzenedicarboxylic acid and 4-aminobenzoic acid were, respectively, used with an appropriate amount of NaOH. S2

3 Figure S1. Solubility test of Ni-based MOC anode materials in acetonitrile at 2 mg ml -1. S3

4 Figure S2. SEM image of the prepared Prussian blue. S4

5 Figure S3. Ex situ energy dispersive X-ray spectrum of a discharged cathode from the cell consisting of Prussian blue as a cathode and NibdcNH2 as an anode at 0.01 V The presence of current collector (stainless steel SS316L) led to the existence of other elements (Cr, Cu) within the spectrum. S5

6 Figure S4. Bode plots and residuals of equivalent models for the measured impedances of cells with Prussian blue cathode and MOCs-type anodes. a) Nibdc, b) NibdcNH2. The interpretation of EIS results was based on the residual of Z factor: residual of Z = Z Z simulate Z 100% (S1) where Z and Z simulate are the modulus of actual and simulated impedances of the system. The residual of Z indicates the difference between simulated impedances of a preferred model and observed impedances. Thus, well matched model will let the residual of Z approach 0. To analyze the observed impedances, the limitation of residual of Z was set at ±10%. S6

7 The diffusion coefficient D (cm 2 s -1 ) was calculated by the following equation: D = W2 yr 2 T 2 2A 2 n 4 F 4 C 2 (S2) where: W y is the reciprocal of the Warburg coefficient, Ss 0.5 ; R is the gas constant, J mol -1 K -1 ; T is the thermodynamic temperature, K; A is the area of the electrode, cm 2 ; n is the valence of Ca 2+ ion; F is the Faraday constant, C mol -1 ; C is the concentration of Ca 2+ ion within the electrolyte, mol cm -3 ; After carrying out the EIS simulation, the values of W y for Nibdc and NibdcNH2 cases were Ss 0.5 and Ss 0.5, respectively. S7

8 Figure S5. Weight deviation and electrical conductivity of graphite foil and stainless steel SS316L foil. The mean and the standard deviation of the mass for graphite foil (Alfa, 99.8%) were 28.7 mg and 0.86 mg cm -2, respectively. S8