Iron Phosphate/Bacteria Composites as Precursors for Textured Electrode Materials with Enhanced Electrochemical Properties

Coordination polymers represent a suitable model to study redox mechanisms in materials where both metal cation and ligand undergo electrochemical reactions and are capable to proceed through reversible multielectron-transfer processes with insertion of cation and anion into their open structures. Designing new coordination polymers for electrochemical energy storage with improved performance relays also on the understanding of their structure-properties relationship. Here, we present a family of copper-based coordination polymer with hexafunctionalized benzene ligands forming a kagome-type layered structure, where the in uence of the functional groups in their structure and electrochemical properties is investigated. Their chemical and structural properties have been explored by means of PXRD, and FTIR and Raman spectroscopies, followed by investigation of their electrochemical performance in Li half-cells by CV and galvanostatic cycling techniques. Ex-situ PXRD, Raman, XPS and ToF-SIMS measurements of cycled electrodes have been carried out providing insights into the redox mechanism of these copper-based coordination polymers as positive electrode materials.<br>

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Deciphering the Structural, Textural, and Electrochemical Properties of Activated BN-Doped Spherical Carbons

Nanomaterials ◽

10.3390/nano9030446 ◽

2019 ◽

Vol 9 (3) ◽

pp. 446 ◽

Cited By ~ 4

Author(s):

Bridget Mutuma ◽

Boitumelo Matsoso ◽

Damilola Momodu ◽

Kabir Oyedotun ◽

Neil Coville ◽

...

Keyword(s):

Electrochemical Properties ◽

Photoelectron Spectroscopy ◽

Electrode Materials ◽

Electrochemical Analysis ◽

Activation Mechanism ◽

Specific Power ◽

Carbon Spheres ◽

Cell Potential ◽

Co Doping ◽

Pyridinic N

In this study, the effect of K2CO3 activation on the structural, textural, and electrochemical properties of carbon spheres (CSs) and boron and nitrogen co-doped carbon spheres (BN-CSs) was evaluated. Activation of the CSs and BN-CSs by K2CO3 resulted in increased specific surface areas and ID/IG ratios. From the X-ray photoelectron spectroscopy (XPS) results, the BN-CSs comprised of 64% pyridinic-N, 24% pyrrolic-N and 7% graphitic-N whereas the activated BN-CSs had 19% pyridinic-N, 40% pyrrolic-N and 22% graphitic-N displaying the effect of activation on the type of N configurations in BN-CSs. A possible BN-co-doping and activation mechanism for the BN-CSs is proposed. Electrochemical analysis of the electrode materials revealed that BN doping, carbon morphology, structure, and porosity played a crucial role in enhancing the capacitive behavior of the CSs. As a proof of concept, a symmetric device comprising the activated BN-CSs displayed a specific power of 800 W kg−1 at a specific current of 1 A g−1 within an operating cell potential of 1.6 V in a 3 M KNO3 electrolyte. The study illustrated for the first time the role of K2CO3 activation in influencing the physical and surface properties of template-free activated BN-CSs as potential electrode materials for energy storage systems.

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