29 research outputs found
High Temperature Carbonized Grass as a High Performance Sodium Ion Battery Anode
Hard carbon is currently
considered the most promising anode candidate
for room temperature sodium ion batteries because of its relatively
high capacity, low cost, and good scalability. In this work, switchgrass
as a biomass example was carbonized under an ultrahigh temperature,
2050 °C, induced by Joule heating to create hard carbon anodes
for sodium ion batteries. Switchgrass derived carbon materials intrinsically
inherit its three-dimensional porous hierarchical architecture, with
an average interlayer spacing of 0.376 nm. The larger interlayer spacing
than that of graphite allows for the significant Na ion storage performance.
Compared to the sample carbonized under 1000 °C, switchgrass
derived carbon at 2050 °C induced an improved initial Coulombic
efficiency. Additionally, excellent rate capability and superior cycling
performance are demonstrated for the switchgrass derived carbon due
to the unique high temperature treatment
High Temperature Carbonized Grass as a High Performance Sodium Ion Battery Anode
Hard carbon is currently
considered the most promising anode candidate
for room temperature sodium ion batteries because of its relatively
high capacity, low cost, and good scalability. In this work, switchgrass
as a biomass example was carbonized under an ultrahigh temperature,
2050 °C, induced by Joule heating to create hard carbon anodes
for sodium ion batteries. Switchgrass derived carbon materials intrinsically
inherit its three-dimensional porous hierarchical architecture, with
an average interlayer spacing of 0.376 nm. The larger interlayer spacing
than that of graphite allows for the significant Na ion storage performance.
Compared to the sample carbonized under 1000 °C, switchgrass
derived carbon at 2050 °C induced an improved initial Coulombic
efficiency. Additionally, excellent rate capability and superior cycling
performance are demonstrated for the switchgrass derived carbon due
to the unique high temperature treatment
Low-Temperature Synthesis of Mesoporous Half-Metallic High-Entropy Spinel Oxide Nanofibers for Photocatalytic CO<sub>2</sub> Reduction
High-entropy oxides (HEOs) exhibit
great prospects owing to their
varied composition, chemical adaptability, adjustable light-absorption
ability, and strong stability. In this study, we report a strategy
to synthesize a series of porous high-entropy spinel oxide (HESO)
nanofibers (NFs) at a low temperature of 400 °C by a sol–gel
electrospinning technique. The key lies in selecting six acetylacetonate
salt precursors with similar coordination abilities, maintaining a
high-entropy disordered state during the transformation from stable
sols to gel NFs. The as-synthesized HESO NFs of (NiCuMnCoZnFe)3O4 show a high specific surface area of 66.48 m2/g, a diverse elemental composition, a dual bandgap, half-metallicity
property, and abundant defects. The diverse elements provide various
synergistic catalytic sites, and oxygen vacancies act as active sites
for electron–hole separation, while the half-metallicity and
dual-bandgap structure offer excellent light absorption ability, thus
expanding its applicability to a wide range of photocatalytic processes.
As a result, the HESO NFs can efficiently convert CO2 into
CH4 and CO with high yields of 8.03 and 15.89 μmol
g–1 h–1, respectively, without
using photosensitizers or sacrificial agents
Low-Temperature Synthesis of Mesoporous Half-Metallic High-Entropy Spinel Oxide Nanofibers for Photocatalytic CO<sub>2</sub> Reduction
High-entropy oxides (HEOs) exhibit
great prospects owing to their
varied composition, chemical adaptability, adjustable light-absorption
ability, and strong stability. In this study, we report a strategy
to synthesize a series of porous high-entropy spinel oxide (HESO)
nanofibers (NFs) at a low temperature of 400 °C by a sol–gel
electrospinning technique. The key lies in selecting six acetylacetonate
salt precursors with similar coordination abilities, maintaining a
high-entropy disordered state during the transformation from stable
sols to gel NFs. The as-synthesized HESO NFs of (NiCuMnCoZnFe)3O4 show a high specific surface area of 66.48 m2/g, a diverse elemental composition, a dual bandgap, half-metallicity
property, and abundant defects. The diverse elements provide various
synergistic catalytic sites, and oxygen vacancies act as active sites
for electron–hole separation, while the half-metallicity and
dual-bandgap structure offer excellent light absorption ability, thus
expanding its applicability to a wide range of photocatalytic processes.
As a result, the HESO NFs can efficiently convert CO2 into
CH4 and CO with high yields of 8.03 and 15.89 μmol
g–1 h–1, respectively, without
using photosensitizers or sacrificial agents
Low-Temperature Synthesis of Mesoporous Half-Metallic High-Entropy Spinel Oxide Nanofibers for Photocatalytic CO<sub>2</sub> Reduction
High-entropy oxides (HEOs) exhibit
great prospects owing to their
varied composition, chemical adaptability, adjustable light-absorption
ability, and strong stability. In this study, we report a strategy
to synthesize a series of porous high-entropy spinel oxide (HESO)
nanofibers (NFs) at a low temperature of 400 °C by a sol–gel
electrospinning technique. The key lies in selecting six acetylacetonate
salt precursors with similar coordination abilities, maintaining a
high-entropy disordered state during the transformation from stable
sols to gel NFs. The as-synthesized HESO NFs of (NiCuMnCoZnFe)3O4 show a high specific surface area of 66.48 m2/g, a diverse elemental composition, a dual bandgap, half-metallicity
property, and abundant defects. The diverse elements provide various
synergistic catalytic sites, and oxygen vacancies act as active sites
for electron–hole separation, while the half-metallicity and
dual-bandgap structure offer excellent light absorption ability, thus
expanding its applicability to a wide range of photocatalytic processes.
As a result, the HESO NFs can efficiently convert CO2 into
CH4 and CO with high yields of 8.03 and 15.89 μmol
g–1 h–1, respectively, without
using photosensitizers or sacrificial agents
Low-Temperature Synthesis of Mesoporous Half-Metallic High-Entropy Spinel Oxide Nanofibers for Photocatalytic CO<sub>2</sub> Reduction
High-entropy oxides (HEOs) exhibit
great prospects owing to their
varied composition, chemical adaptability, adjustable light-absorption
ability, and strong stability. In this study, we report a strategy
to synthesize a series of porous high-entropy spinel oxide (HESO)
nanofibers (NFs) at a low temperature of 400 °C by a sol–gel
electrospinning technique. The key lies in selecting six acetylacetonate
salt precursors with similar coordination abilities, maintaining a
high-entropy disordered state during the transformation from stable
sols to gel NFs. The as-synthesized HESO NFs of (NiCuMnCoZnFe)3O4 show a high specific surface area of 66.48 m2/g, a diverse elemental composition, a dual bandgap, half-metallicity
property, and abundant defects. The diverse elements provide various
synergistic catalytic sites, and oxygen vacancies act as active sites
for electron–hole separation, while the half-metallicity and
dual-bandgap structure offer excellent light absorption ability, thus
expanding its applicability to a wide range of photocatalytic processes.
As a result, the HESO NFs can efficiently convert CO2 into
CH4 and CO with high yields of 8.03 and 15.89 μmol
g–1 h–1, respectively, without
using photosensitizers or sacrificial agents
Three-Dimensional Printable High-Temperature and High-Rate Heaters
High temperature heaters are ubiquitously
used in materials synthesis
and device processing. In this work, we developed three-dimensional
(3D) printed reduced graphene oxide (RGO)-based heaters to function
as high-performance thermal supply with high temperature and ultrafast
heating rate. Compared with other heating sources, such as furnace,
laser, and infrared radiation, the 3D printed heaters demonstrated
in this work have the following distinct advantages: (1) the RGO based
heater can operate at high temperature up to 3000 K because of using
the high temperature-sustainable carbon material; (2) the heater temperature
can be ramped up and down with extremely fast rates, up to ∼20 000
K/second; (3) heaters with different shapes can be directly printed
with small sizes and onto different substrates to enable heating anywhere.
The 3D printable RGO heaters can be applied to a wide range of nanomanufacturing
when precise temperature control in time, placement, and the ramping
rate are important
Three-Dimensional Printable High-Temperature and High-Rate Heaters
High temperature heaters are ubiquitously
used in materials synthesis
and device processing. In this work, we developed three-dimensional
(3D) printed reduced graphene oxide (RGO)-based heaters to function
as high-performance thermal supply with high temperature and ultrafast
heating rate. Compared with other heating sources, such as furnace,
laser, and infrared radiation, the 3D printed heaters demonstrated
in this work have the following distinct advantages: (1) the RGO based
heater can operate at high temperature up to 3000 K because of using
the high temperature-sustainable carbon material; (2) the heater temperature
can be ramped up and down with extremely fast rates, up to ∼20 000
K/second; (3) heaters with different shapes can be directly printed
with small sizes and onto different substrates to enable heating anywhere.
The 3D printable RGO heaters can be applied to a wide range of nanomanufacturing
when precise temperature control in time, placement, and the ramping
rate are important
Rapid, in Situ Synthesis of High Capacity Battery Anodes through High Temperature Radiation-Based Thermal Shock
High
capacity battery electrodes require nanosized components to avoid
pulverization associated with volume changes during the charge–discharge
process. Additionally, these nanosized electrodes need an electronically
conductive matrix to facilitate electron transport. Here, for the
first time, we report a rapid thermal shock process using high-temperature
radiative heating to fabricate a conductive reduced graphene oxide
(RGO) composite with silicon nanoparticles. Silicon (Si) particles
on the order of a few micrometers are initially embedded in the RGO
host and in situ transformed into 10–15 nm nanoparticles in
less than a minute through radiative heating. The as-prepared composites
of ultrafine Si nanoparticles embedded in a RGO matrix show great
performance as a Li-ion battery (LIB) anode. The in situ nanoparticle
synthesis method can also be adopted for other high capacity battery
anode materials including tin (Sn) and aluminum (Al). This method
for synthesizing high capacity anodes in a RGO matrix can be envisioned
for roll-to-roll nanomanufacturing due to the ease and scalability
of this high-temperature radiative heating process
Garnet Solid Electrolyte Protected Li-Metal Batteries
Garnet-type
solid state electrolyte (SSE) is a promising candidate
for high performance lithium (Li)-metal batteries due to its good
stability and high ionic conductivity. One of the main challenges
for garnet solid state batteries is the poor solid–solid contact
between the garnet and electrodes, which results in high interfacial
resistance, large polarizations, and low efficiencies in batteries.
To address this challenge, in this work gel electrolyte is used as
an interlayer between solid electrolyte and solid electrodes to improve
their contact and reduce their interfacial resistance. The gel electrolyte
has a soft structure, high ionic conductivity, and good wettability.
Through construction of the garnet/gel interlayer/electrode structure,
the interfacial resistance of the garnet significantly decreased from
6.5 × 10<sup>4</sup> to 248 Ω cm<sup>2</sup> for the cathode
and from 1.4 × 10<sup>3</sup> to 214 Ω cm<sup>2</sup> for
the Li-metal anode, successfully demonstrating a full cell with high
capacity (140 mAh/g for LiFePO<sub>4</sub> cathode) over 70 stable
cycles in room temperature. This work provides a binary electrolyte
consisting of gel electrolyte and solid electrolyte to address the
interfacial challenge of solid electrolyte and electrodes and the
demonstrated hybrid battery presents a promising future for battery
development with high energy and good safety