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@ARTICLE{Siher:639333,
author = {Siher, Anja and Maver, Ksenija and Arcon, Iztok and Mavric,
Andraz},
title = {{C}arbonate {F}ormation during {N}ickel {H}ydroxide
{P}recipitation {R}educes {P}seudocapacitive {P}erformance},
journal = {Chemistry of materials},
volume = {37},
number = {19},
issn = {0897-4756},
address = {Washington, DC},
publisher = {American Chemical Society},
reportid = {PUBDB-2025-04434},
pages = {7813 - 7822},
year = {2025},
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.},
cin = {DOOR ; HAS-User},
ddc = {540},
cid = {I:(DE-H253)HAS-User-20120731},
pnm = {6G3 - PETRA III (DESY) (POF4-6G3) / FS-Proposal: I-20230893
EC (I-20230893-EC) / FS-Proposal: I-20240152 EC
(I-20240152-EC)},
pid = {G:(DE-HGF)POF4-6G3 / G:(DE-H253)I-20230893-EC /
G:(DE-H253)I-20240152-EC},
experiment = {EXP:(DE-H253)P-P65-20150101},
typ = {PUB:(DE-HGF)16},
doi = {10.1021/acs.chemmater.5c01467},
url = {https://bib-pubdb1.desy.de/record/639333},
}