Supporting information A MetalOrganic FrameworkDerived Porous Cobalt Manganese Oxide Bifunctional Electrocatalyst for Hybrid NaAir/Seawater Batteries Mari Abirami a,, Soo Min Hwang a,, *, Juchan Yang a, Sirugaloor Thangavel Senthilkumar a, Junsoo Kim a, WooSeok Go a, Baskar Senthilkumar a, HyunKon Song a, and Youngsik Kim a,b, * a School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), UNISTgil 50, Ulsan 44919, Republic of Korea b Energy Materials and Devices Lab, 4TOONE Corporation, UNISTgil 50, Ulsan 44919, Republic of Korea These authors contributed equally to this work. *Corresponding author: smhwang@unist.ac.kr (S.M. Hwang); ykim@unist.ac.kr (Y. Kim) S1
Figure S1. SEM image (a), XRD pattern (b), and TGA curve (c) of the Mn 3 [Co(CN) 6 ] 2 nh 2 O nanocubes, and SEM image of the CMO nanoparticles (d). The marks a and d in Fig. S1c correspond to 30 C and 430 C, respectively. S2
Figure S2. SAED (a) and FFT (b) patterns of the CMO sample. All the Debye rings of the SAED pattern and the FFT pattern (with a zone axis of [14 1 ] ) correspond to the tetragonal (Co,Mn)(Co,Mn) 2 O 4 phase (I41/amdS; PDF#180408). S3
Figure S3. N 2 sorption isotherms and size distribution graph (inset) of Mn 3 [Co(CN) 6 ] 2 nh 2 O nanocubes. The graph shows a typical type I isotherm and a bimodal pore size distribution. S4
Table S1. Comparison of the catalytic activities of cobaltmanganese oxide toward the ORR and OER with previous literatures. ORR activity OER activity Catalysts E onset (E 1/2 ) [V vs. RHE] ΔV * [V] E (η) ** @10 ma cm 2 [V vs. RHE] Solution Ref. tco 1.3 Mn 1.7 O 4±δ (+CB) 0.86 (0.74) 0.12 1.69 (0.46) 0.1 M NaOH 0.67 (0.49) 0.13 1.86 (0.63) seawater (ph~8) This work Co 0.51 Mn 0.49 O/NCNT 0.96 (0.84) 1.57 (0.34) 1 M KOH S1 cmnco 2 O 4 /NrmGO 0.95 ~0.05 ~1.57 (~0.34) 1 M KOH cmnco 2 O 4 (+CB) ~0.85 ~0.15 1 M KOH S2 tcomn 2 O 4 NWs(+CB) ~0.87 ~1.67 (~0.44) 0.1 M KOH S3 cmn 1.4 Co 1.6 O 4 (+CB) tmn 1.9 Co 1.1 O 4 (+CB) ~0.88 (0.75) ~0.90 ~0.07 ~0.05 0.1 M KOH S4 ccomn 2 O 4 /C 0.95 (0.85) 0.01 ~1.78 (~0.55) ccomn 2 O 4 (+CB) 0.91 (0.73) 0.05 0.1 M KOH S5 tcomn 2 O 4 (+CB) 0.86 (0.71) 0.10 cmnco 2 O 4 NFs(+CB) tcomn 2 O 4 NFs(+CB) 0.92 V 0.85 V 0.1 M KOH S6 dpmnco 2 O 4 /NrGO dpmnco 2 O 4 /CNT tcomn 2 O 4 /rgo 0.09 V vs. Ag/AgCl 0.11 V vs. Ag/AgCl ~ 0.5 V vs. Hg/Hg 2 SO 4 0 0.02 0.09 ~0.72 V vs. Ag/AgCl ~0.79 V vs. Ag/AgCl E onset ~0.43 V vs. Hg/Hg 2 SO 4 0.1 M KOH S7 0.1 M KOH S8 ΔV*: Voltage difference from the E onset of benchmark Pt/C used in the corresponding literatures E(η)**: measured potential and overpotential (vs. RHE) for OER at 10 ma cm 2 t, c, and dp represent tetragonal, cubic, and dual (mixed) spinel phases, respectively. (+CB) indicates using a mixture with carbon black nanoparticles. Part of the specific values (~***) was taken from the graphs in the literatures. S5
Figure S4. The initial chargedischarge voltage profiles of seawater batteries with the CMO catalyst at different current densities of 0.01 0.1 ma cm 2. S6
Figure S5. Galvanostatic chargedischarge voltage profiles of the halfcell with the hard carbon electrode at 20 ma g 1 during 20 cycles. S7
Figure S6. XRD pattern (a) and XPS spectra of Co 2p (b), Mn 2p (c), and O 1s (d) of the CMO catalyst after 100 cycles. The bottom in (a) shows the reference XRD pattern of tetragonal (Co,Mn) 3 O 4 phase (JCPDS No. 180408). The broad peaks (marked by *) were arose from the remnant carbon black powders attached on the catalyst powders. S8
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