Journal Article

PUBDB-2025-04434

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Carbonate Formation during Nickel Hydroxide Precipitation Reduces Pseudocapacitive Performance

Siher, A. (First author)Extern* ; Maver, K.Extern* ; Arcon, I.Extern* ; Mavric, A. (Corresponding author)Extern*

2025
American Chemical Society Washington, DC

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Please use a persistent id in citations: doi:10.1021/acs.chemmater.5c01467  doi:10.3204/PUBDB-2025-04434

Abstract: Nickel hydroxide (Ni(OH)$_2$) is a promising pseudocapacitive material owing to its high theoretical capacitance and reversible Ni$^{2+}$/Ni$^{3+}$ redox activity. Here we demonstrate that carbonate incorporation during hydrothermal synthesis is the key structural factor limiting its electrochemical performance. Ni(OH)$_2$ was prepared using hexamethylenetetramine (HMT) and urea at different synthesis temperatures, and carbonate incorporation was quantified by XRD, FTIR, Raman, TGA-MS, and CaCO$_3$ precipitation. HMT-derived samples at a low temperature (80 °C) formed a turbostratic α-phase with interlayer water, delivering the highest specific capacitance (∼870 F g$^{-1}$ at 1 A g$^{-1}$) and excellent cycling stability (92–96% retention after 1000 cycles). In contrast, increasing the synthesis temperature promoted carbonate incorporation and crystallization into nickel carbonate hydroxide, reducing the interlayer spacing and surface area and increasing charge-transfer resistance. Urea-derived samples incorporated carbonate at all synthesis temperatures, yielding phases with capacitances an order of magnitude lower than those of HMT analogues. Electrochemical impedance spectroscopy confirmed that carbonate incorporation blocks redox-active sites and hinders ion/electron transport. These results provide a quantitative mechanistic understanding of how carbonate formation governs transition metal layered hydroxide performance, establishing guidelines for optimizing hydrothermal synthesis of pseudocapacitive electrodes.

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Contributing Institute(s):

1. DOOR-User (DOOR ; HAS-User)

Research Program(s):

1. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)
2. FS-Proposal: I-20230893 EC (I-20230893-EC) (I-20230893-EC)
3. FS-Proposal: I-20240152 EC (I-20240152-EC) (I-20240152-EC)

Experiment(s):

1. PETRA Beamline P65 (PETRA III)

Appears in the scientific report 2025

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Database coverage:
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