2 research outputs found
Stabilizing Lithium-Metal Host Anodes by Covalently Binding MgF<sub>2</sub> Nanodots to Honeycomb Carbon Nanofibers
Constructing lithiophilic carbon
hosts has been regarded as an
effective strategy for inhibiting Li dendrite formation and mitigating
the volume expansion of Li metal anodes. However, the limitation of
lithiophilic carbon hosts by conventional surface decoration methods
over long-term cycling hinders their practical application. In this
work, a robust host composed of ultrafine MgF2 nanodots
covalently bonded to honeycomb carbon nanofibers (MgF2/HCNFs)
is created through an in situ solid-state reaction. The composite
exhibits ultralight weight, excellent lithiophilicity, and structural
stability, contributing to a significantly enhanced energy efficiency
and lifespan of the battery. Specifically, the strong covalent bond
not only prevents MgF2 nanodots from migrating and aggregating
but also enhances the binding energy between Mg and Li during the
molten Li infusion process. This allows for the effective and stable
regulation of repeated Li plating/stripping. As a result, the MgF2/HCNF-Li electrode delivers a high Coulombic efficiency of
97% after 200 cycles, cycling stably for more than 2000 h. Furthermore,
the full cells with a LiFePO4 cathode achieve a capacity
retention of 85% after 500 cycles at 0.5C. This work provides a strategy
to guide dendrite-free Li deposition patterns toward the development
of high-performance Li metal batteries
Facile and Scalable Synthesis of Self-Supported Zn-Doped CuO Nanosheet Arrays for Efficient Nitrate Reduction to Ammonium
CuO has been regarded as a promising catalyst for the
electrochemical
reduction of nitrate (NO3–RR) to ammonium
(NH3); however, the intrinsic activity is greatly restricted
by its poor electrical property. In this work, self-supported Zn-doped
CuO nanosheet arrays (Zn–CuO NAs) are synthesized for NO3–RR, where the Zn dopant regulates the electronic
structure of CuO to significantly accelerate the interfacial charge
transfer and inner electron transport kinetics. The Zn–CuO
NAs are constructed by a one-step etching of commercial brass (Cu64Zn36 alloy) in 0.1 M NaOH solution, which experiences
a corrosion–oxidation–reconstruction process. Initially,
the brass undergoes a dealloying procedure to produce nanosized Cu,
which is immediately oxidized to the Cu2O unit with a low
valence state. Subsequently, Cu2O is further oxidized to
the CuO unit and reconstructed into nanosheets with the coprecipitation
of Zn2+. For NO3–RR, Zn–CuO
NAs show a high NH3 production rate of 945.1 μg h–1 cm–2 and a Faradaic efficiency
of up to 95.6% at −0.7 V in 0.1 M Na2SO4 electrolyte with 0.01 M NaNO3, which outperforms the
majority of the state-of-the-art catalysts. The present work offers
a facile yet very efficient strategy for the scale-up synthesis of
Zn–CuO NAs for high-performance NH3 production from
NO3–RR