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van der Heijden O, Eggebeen JJJ, Trzesniowski H, Deka N, Golnak R, Xiao J, van Rijn M, Mom RV, Koper MTM. Li + Cations Activate NiFeOOH for Oxygen Evolution in Sodium and Potassium Hydroxide. Angew Chem Int Ed Engl 2024; 63:e202318692. [PMID: 38323697 DOI: 10.1002/anie.202318692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/31/2024] [Accepted: 02/01/2024] [Indexed: 02/08/2024]
Abstract
The efficiency of electrolysis is reduced due to the sluggish oxygen evolution reaction (OER). Besides catalyst properties, electrocatalytic activity also depends on the interaction of the electrocatalyst with the electrolyte. Here, we show that the addition of small amounts of Li+ to Fe-free NaOH or KOH electrolytes activates NiFeOOH for the OER compared to single-cation electrolytes. Moreover, the activation was maintained when the solution was returned to pure NaOH. Importantly, we show that the origin of activation by Li+ cations is primarily non-kinetic in nature, as the OER onset for the mixed electrolyte does not change and the Tafel slope at low current density is ~30 mV/dec in both electrolytes. However, the increase of the apparent Tafel slope remains lower at increasing current densities in the presence of Li+. Based on electrochemical quartz crystal microbalance and in situ X-ray absorption spectroscopy measurements, we show that this reduction of non-kinetic effects is due to enhanced intercalation of sodium, water and hydroxide. This enhanced electrolyte penetration facilitates the OER, especially at higher current densities and for increased catalyst loading. Our work shows that mixed electrolytes where distinct cations can have different roles provide a simple and promising strategy towards improved OER rates.
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Affiliation(s)
- Onno van der Heijden
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, the Netherlands
| | - Jordy J J Eggebeen
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, the Netherlands
| | - Hanna Trzesniowski
- Department of Atomic-Scale Dynamics in Light-Energy Conversion, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Nipon Deka
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, the Netherlands
| | - Ronny Golnak
- Department of Highly Sensitive X-Ray Spectroscopy, Helmholtz-Zentrum Berlin für Materialien und Energie, 14109, Berlin, Germany
| | - Jie Xiao
- Department of Highly Sensitive X-Ray Spectroscopy, Helmholtz-Zentrum Berlin für Materialien und Energie, 14109, Berlin, Germany
| | - Maartje van Rijn
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, the Netherlands
| | - Rik V Mom
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, the Netherlands
| | - Marc T M Koper
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, the Netherlands
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Beladi-Mousavi SM, Sadaf S, Mahmood AM, Walder L. High Performance Poly(viologen)-Graphene Nanocomposite Battery Materials with Puff Paste Architecture. ACS Nano 2017; 11:8730-8740. [PMID: 28836762 DOI: 10.1021/acsnano.7b02310] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Four linear poly(viologens) (PV1, PV2: phenylic, PV3: benzylic, and PV4: aliphatic) in tight molecular contact with reduced graphene oxide (rGO), that is, PV@rGO, were prepared and used as anodic battery materials. These composites show exceptionally high, areal, volumetric, and current densities, for example, PV1@rGO composites (with 15 wt % rGO, corresponding to 137 mAh g-1) show 13.3 mAh cm-2 at 460 μm and 288 mAh cm-3 with 98% Coulombic efficiency at current densities up to 1000 A g-1, better than any reported organic materials. These remarkable performances are based on (i) molecular self-assembling of PVs on individual GO sheets yielding colloidal PV@GO and (ii) efficient GO/rGO transformation electrocatalyzed by PVs. Ion breathing during charging/discharging was studied by electrochemical quartz crystal microbalance and electrochemical atomic force microscopy revealing an absolute reversible and strongly anisotropic thickness oscillation of PV1@rGO at a right angle to the macroscopic current collector. It is proposed that such stress-free breathing is the key property for good cyclability of the battery material. The anisotropy is related to a puff paste architecture of rGO sheets parallel to the macroscopic current collector. A thin graphite sheet electrode with an areal capacity of 1.23 mAh cm-2 is stable over 200 bending cycles, making the material applicable for wearable electronics. The polymer acts as a lubricant between the rGO layers if shearing forces are active.
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Affiliation(s)
- Seyyed Mohsen Beladi-Mousavi
- Institute of Chemistry of New Materials, Center of Physics and Chemistry of New Materials, University of Osnabrück , Barbarastr. 7, Osnabrück D-49069 Germany
| | - Shamaila Sadaf
- Institute of Chemistry of New Materials, Center of Physics and Chemistry of New Materials, University of Osnabrück , Barbarastr. 7, Osnabrück D-49069 Germany
| | - Arsalan Mado Mahmood
- Institute of Chemistry of New Materials, Center of Physics and Chemistry of New Materials, University of Osnabrück , Barbarastr. 7, Osnabrück D-49069 Germany
| | - Lorenz Walder
- Institute of Chemistry of New Materials, Center of Physics and Chemistry of New Materials, University of Osnabrück , Barbarastr. 7, Osnabrück D-49069 Germany
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