6 research outputs found
Evolution of Useless Iron Rust into Uniform α‑Fe<sub>2</sub>O<sub>3</sub> Nanospheres: A Smart Way to Make Sustainable Anodes for Hybrid Ni–Fe Cell Devices
The large amount
of iron rust yielded in steel industries is undoubtedly
a useless and undesired product since its substantial formation and
recycle/smelting would give rise to enormous financial costs and environmental
pollution issues. To best reuse such rusty wastes, we herein propose
a smart and applicable method to convert them into uniform α-Fe<sub>2</sub>O<sub>3</sub> nanospheres. Only after a simple and conventional
hydrothermal treatment in HNO<sub>3</sub> solution, nearly all of
the iron rust can evolve into sphere-like α-Fe<sub>2</sub>O<sub>3</sub> products with a typical size of ∼30 nm. When serving
as actives for electrochemical energy storage, the <i>in situ</i> generated α-Fe<sub>2</sub>O<sub>3</sub> nanospheres exhibit
prominent anodic performance, with a maximum specific capacity of
∼269 mAh/g at ∼0.3 A/g, good rate capabilities (∼67.3
mAh/g still retains even at a high rate up to 12.3 A/g), and negligible
capacity degradation among 500 cycles. Furthermore, by paring with
activated carbons/Ni cathodes, a unique full hybrid Ni–Fe cell
is constructed. The assembled full devices can be operated reversibly
at a voltage as high as ∼1.8 V in aqueous electrolytes, capable
of delivering both high specific energy and power densities with maximum
values of ∼131.25 Wh/kg and ∼14 kW/kg, respectively.
Our study offers a scalable and effective route to transform rusty
wastes into useful α-Fe<sub>2</sub>O<sub>3</sub> nanospheres,
providing an economic way to make sustainable anodes for energy-storage
applications and also a platform to develop advanced Fe-based nanomaterials
for other wide potential applications
FeF<sub>3</sub>@Thin Nickel Ammine Nitrate Matrix: Smart Configurations and Applications as Superior Cathodes for Li-Ion Batteries
Iron
fluorides (FeF<sub><i>x</i></sub>) for Li-ion battery
cathodes are still in the stage of intensive research due to their
low delivery capacity and limited lifetime. One critical reason for
cathode degradation is the severe aggregation of FeF<sub><i>x</i></sub> nanocrystals upon long-term cycling. To maximize the capacity
and cyclability of these cathodes, we propose herein a novel and applicable
method using a thin-layered nickel ammine nitrate (NAN) matrix as
a feasible encapsulation material to disperse the FeF<sub>3</sub> nanoparticles.
Such core–shell hybrids with smart configurations are constructed
via a green, scalable, in situ encapsulation approach. The outer thin-film
NAN matrix with prominent electrochemical stability can keep the FeF<sub>3</sub> nanoactives encapsulated throughout the cyclic testing, protecting
them from adverse aggregation into bulk crystals and thus leading
to drastic improvements of electrode behaviors (e.g., high electrode
capacity up to ∼423 mA h g<sup>–1</sup>, greatly prolonged
cyclic period, and promoted rate capabilities). This present work
may set up a new and general platform to develop intriguing core–shell
hybrid cathodes for Li-ion batteries, not only for FeF<sub><i>x</i></sub> but also for a wide spectrum of other cathode materials
Smart Magnetic Interaction Promotes Efficient and Green Production of High-Quality Fe<sub>3</sub>O<sub>4</sub>@Carbon Nanoactives for Sustainable Aqueous Batteries
Efficient and green
production of monodispersed Fe<sub>3</sub>O<sub>4</sub>@carbon (C)
nanoactives for commercial aqueous battery usage
still remains a great challenge due to issues related to tedious hybrid
fabrication and purification procedures. Herein, we put forward an
interesting applicable synthetic strategy via a general polymeric
process and simple magnetic purification treatments, enabling low-cost
and massive production of high-quality Fe<sub>3</sub>O<sub>4</sub>@C hybrids. In such core–shell configurations, all Fe<sub>3</sub>O<sub>4</sub> nanoparticles are tightly encapsulated in permeable <i>N</i>-doped C nanoreactors, showing notable nanostructured superiorities
as feasible anodes for aqueous batteries. When tested, the Fe<sub>3</sub>O<sub>4</sub>@C nanoactives exhibit outstanding anodic performance
comprising pretty high electrochemical activity/capacity, greatly
prolonged cyclic lifespan in contrast to bare Fe<sub>3</sub>O<sub>4</sub> counterparts, and prominent rate capabilities. The as-assembled
Ni/Fe full cells can even deliver a high energy/power density up to
∼135 Wh kg<sup>–1</sup>/11.5 kW kg<sup>–1</sup>, further demonstrating their good potential in practical applications.
Our smart magnetic purification strategy may hold great promise in
addressing critical issues of producing high-quality and affordable
Fe<sub>3</sub>O<sub>4</sub>@C hybrids, not only for energy-storage
fields but also in other broad ranges covering catalysts and biosensors
Engineering 3D Interpenetrated ZIF‑8 Network in Poly(ethylene oxide) Composite Electrolyte for Fast Lithium-Ion Conduction and Effective Lithium-Dendrite Inhibition
A novel 3D ZIF-8 network-reinforced polyethylene oxide
(PEO) composite
polymer electrolyte (Z-C-PAN-PEO) is successfully built, in which
the network with an interpenetrated structure is tactfully developed
by in situ assembling ZIF-8 nanoparticles on electrospinning carboxylated
polyacrylonitrile (C-PAN) nanofiber surfaces. ZIF-8 with high porosity
and unsaturated open metal sites will act as the bridge between C-PAN
nanofibers and the PEO matrix. It is proven that the selected ZIF-8
can play a significant role in facilitating Li+ conduction
and transference by effectively interacting with the oxygen atoms
of C–O–C to promote the segmental movement of PEO and
immobilizing TFSI– anions to release more free Li+. The 3D interpenetrating structure of Z-C-PAN further enables
the conduction channels more consecutive and long-ranged, endowing
the Z-C-PAN-PEO electrolyte with an optimum ionic conductivity of
4.39 × 10–4 S cm–1 and a
boosted Li+ transference number of 0.42 at 60 °C.
Other improvements occurring in the reinforced electrolytes are the
broaden electrochemical stability window of ∼4.9 V and sufficient
mechanical strength. Consequently, the stable Li-plating/stripping
for 1000 cycles at 0.1 mA cm–1 witnesses the splendid
compatibility against Li dendrite. The cycling performance of LiFePO4/Z-C-PAN-PEO/Li cells with a reversible capacity of 116.2
mAh g–1 after 600 cycles at 0.2 C guarantees the
long-term running potential in lithium metal batteries. This study
puts forward new insights in designing and exploiting the active role
of MOFs for high-performance solid polymer electrolytes
Efficient Production of Coaxial Core–Shell MnO@Carbon Nanopipes for Sustainable Electrochemical Energy Storage Applications
Adverse
structural changes and poor intrinsic electrical conductivity
as well as the lack of an environmentally benign synthesis for MnO
species are major factors to limit their further progress on electrochemical
energy storage applications. To overcome the above constraints, the
development of reliable and scalable techniques to confine MnO within
a conductive matrix is highly desired. We herein propose an efficient
and reliable way to fabricate coaxial core–shell hybrids of
MnO@carbon nanopipes merely via simple ultrasonication and calcination
treatments. The evolved MnO nanowires disconnected/confined in pipe-like
carbon nanoreactors show great promise in sustainable supercapacitors
(SCs) and Li-ion battery (LIB) applications. When used in SCs, such
core–shell MnO@carbon configurations exhibit outstanding positive
and negative capacitive behaviors in distinct aqueous electrolyte
systems. This hybrid can also function as a prominent LIB electrode,
demonstrating a high reversible capacity, excellent rate capability,
long lifespan, and stable battery operation. The present work may
shed light on effective and scalable production of Mn-based hybrids
for practical applications, not merely for energy storage but also
in other broad fields such as catalysts and biosensors
One-Dimensional Integrated MnS@Carbon Nanoreactors Hybrid: An Alternative Anode for Full-Cell Li-Ion and Na-Ion Batteries
Manganese
sulfide (MnS) has triggered great interest as an anode
material for rechargeable Li-ion/Na-ion batteries (LIBs/SIBs) because
of its low cost, high electrochemical activity, and theoretical capacity.
Nevertheless, the practical application is greatly hindered by its
rapid capacity decay lead by inevitable active dissolutions and volume
expansions in charge/discharge cycles. To resolve the above issues
in LIBs/SIBs, we herein put forward the smart construction of MnS
nanowires embedded in carbon nanoreactors (MnS@C NWs) via a facile
solution method followed by a scalable in situ sulfuration treatment.
This engineering protocol toward electrode architectures/configurations
endows integrated MnS@C NWs anodes with large specific capacity (with
a maximum value of 847 mA h g<sup>–1</sup> in LIBs and 720
mA h g<sup>–1</sup> in SIBs), good operation stability, excellent
rate capabilities, and prolonged cyclic life span. To prove their
potential real applications, we have established the full cells (for
LIBs, MnS@C//LiFePO<sub>4</sub>; for SIBs, MnS@C//Na<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub>), both of which are capable of
showing remarkable specific capacities, outstanding rate performance,
and superb cyclic endurance. This work offers a scalable, simple,
and efficient evolution method to produce the integrated hybrid of
MnS@C NWs, providing useful inspiration/guidelines for anodic applications
of metal sulfides in next-generation power sources