4 research outputs found
Stable Harsh-Temperature Lithium Metal Batteries Enabled by Tailoring Solvation Structure in Ether Electrolytes
For
lithium metal batteries (LMBs), the elevated operating
temperature
results in severe capacity fading and safety issues due to unstable
electrode–electrolyte interphases and electrolyte solvation
structures. Therefore, it is crucial to construct advanced electrolytes
capable of tolerating harsh environments to ensure stable LMBs. Here,
we proposed a stable localized high-concentration electrolyte (LHCE)
by introducing the highly solvating power solvent diethylene glycol
dimethyl ether (DGDME). Computational and experimental evidence discloses
that the original DGDME-LHCE shows favorable features for high-temperature
LMBs, including high Li+-binding stability, electro-oxidation
resistance, thermal stability, and nonflammability. The tailored solvated
sheath structure achieves the preferred decomposition of anions, inducing
the stable (cathode and Li anode)/interphases simultaneously, which
enables a homogeneous Li plating–stripping behavior on the
anode side and a high-voltage tolerance on the cathode side. For the
Li||Li cells coupled with DGDME-LHCE, they showcase outstanding reversibility
(a long lifespan of exceeding 1900 h). We demonstrate exceptional
cyclic stability (∼95.59%, 250 cycles), high Coulombic efficiency
(>99.88%), and impressive high-voltage (4.5 V) and high-temperature
(60 °C) performances in Li||NCM523 cells using DGDME-LHCE. Our
advances shed light on an encouraging ether electrolyte tactic for
the Li-metal batteries confronted with stringent high-temperature
challenges
Stable Harsh-Temperature Lithium Metal Batteries Enabled by Tailoring Solvation Structure in Ether Electrolytes
For
lithium metal batteries (LMBs), the elevated operating
temperature
results in severe capacity fading and safety issues due to unstable
electrode–electrolyte interphases and electrolyte solvation
structures. Therefore, it is crucial to construct advanced electrolytes
capable of tolerating harsh environments to ensure stable LMBs. Here,
we proposed a stable localized high-concentration electrolyte (LHCE)
by introducing the highly solvating power solvent diethylene glycol
dimethyl ether (DGDME). Computational and experimental evidence discloses
that the original DGDME-LHCE shows favorable features for high-temperature
LMBs, including high Li+-binding stability, electro-oxidation
resistance, thermal stability, and nonflammability. The tailored solvated
sheath structure achieves the preferred decomposition of anions, inducing
the stable (cathode and Li anode)/interphases simultaneously, which
enables a homogeneous Li plating–stripping behavior on the
anode side and a high-voltage tolerance on the cathode side. For the
Li||Li cells coupled with DGDME-LHCE, they showcase outstanding reversibility
(a long lifespan of exceeding 1900 h). We demonstrate exceptional
cyclic stability (∼95.59%, 250 cycles), high Coulombic efficiency
(>99.88%), and impressive high-voltage (4.5 V) and high-temperature
(60 °C) performances in Li||NCM523 cells using DGDME-LHCE. Our
advances shed light on an encouraging ether electrolyte tactic for
the Li-metal batteries confronted with stringent high-temperature
challenges
Facile Preparation of Well-Dispersed CeO<sub>2</sub>–ZnO Composite Hollow Microspheres with Enhanced Catalytic Activity for CO Oxidation
In
this article, well-dispersed CeO<sub>2</sub>–ZnO composite
hollow microspheres have been fabricated through a simple chemical
reaction followed by annealing treatment. Amorphous zinc–cerium
citrate hollow microspheres were first synthesized by dispersing zinc
citrate hollow microspheres into cerium nitrate solution and then
aging at room temperature for 1 h. By calcining the as-produced zinc–cerium
citrate hollow microspheres at 500 °C for 2 h, CeO<sub>2</sub>–ZnO composite hollow microspheres with homogeneous composition
distribution could be harvested for the first time. The resulting
CeO<sub>2</sub>–ZnO composite hollow microspheres exhibit enhanced
activity for CO oxidation compared with CeO<sub>2</sub> and ZnO, which
is due to well-dispersed small CeO<sub>2</sub> particles on the surface
of ZnO hollow microspheres and strong interaction between CeO<sub>2</sub> and ZnO. Moreover, when Au nanoparticles are deposited on
the surface of the CeO<sub>2</sub>–ZnO composite hollow microspheres,
the full CO conversion temperature of the as-produced 1.0 wt % Au–CeO<sub>2</sub>–ZnO composites reduces from 300 to 60 °C in comparison
with CeO<sub>2</sub>–ZnO composites. The significantly improved
catalytic activity may be ascribed to the strong synergistic interplay
between Au nanoparticles and CeO<sub>2</sub>–ZnO composites
Layered-MnO<sub>2</sub> Nanosheet Grown on Nitrogen-Doped Graphene Template as a Composite Cathode for Flexible Solid-State Asymmetric Supercapacitor
Flexible
solid-state supercapacitors provide a promising energy-storage
alternative for the rapidly growing flexible and wearable electronic
industry. Further improving device energy density and developing a
cheap flexible current collector are two major challenges in pushing
the technology forward. In this work, we synthesize a nitrogen-doped
graphene/MnO<sub>2</sub> nanosheet (NGMn) composite by a simple hydrothermal
method. Nitrogen-doped graphene acts as a template to induce the growth
of layered δ-MnO<sub>2</sub> and improves the electronic conductivity
of the composite. The NGMn composite exhibits a large specific capacitance
of about 305 F g<sup>–1</sup> at a scan rate of 5 mV s<sup>–1</sup>. We also create a cheap and highly conductive flexible
current collector using Scotch tape. Flexible solid-state asymmetric
supercapacitors are fabricated with NGMn cathode, activated carbon
anode, and PVA–LiCl gel electrolyte. The device can achieve
a high operation voltage of 1.8 V and exhibits a maximum energy density
of 3.5 mWh cm<sup>–3</sup> at a power density of 0.019 W cm<sup>–3</sup>. Moreover, it retains >90% of its initial capacitance
after 1500 cycles. Because of its flexibility, high energy density,
and good cycle life, NGMn-based flexible solid state asymmetric supercapacitors
have great potential for application in next-generation portable and
wearable electronics