An Elastomeric Lithium-Conducting Interlayer for High-Performance LATP-Based Lithium Metal Batteries.

In response to the critical challenges of interfacial impedance and volumetric changes in Li(1+x)AlxTi(2­x)(PO4)3 (LATP)-based lithium metal batteries, an elastomeric lithium-conducting interlayer fabricates from fluorinated hydrogenated nitrile butadiene rubber (F-HNBR) matrix is introduced herein. Owing to the vulcanization, vapor-phase fluorination, and plasticization processes, the lithium-conducting interlayer exhibits a high elasticity of 423%, exceptional fatigue resistance (10 000 compression cycles), superior ionic conductivity of 6.3 × 10-4 S cm-1, and favorable lithiophilicity, rendering it an ideal buffer layer. By integrating the F-HNBR interlayer, the LATP-based lithium symmetric cells demonstrate an extended cycle life of up to 1600 h at 0.1 mA cm-2 and can also endure deep charge/discharge cycles (0.5 mAh cm-2) for the same duration. Furthermore, the corresponding lithium metal full cells achieve 500 cycles at 0.5 C with 98.3% capacity retention and enable a high-mass-loading cathode of 11.1 mg cm-2 to operate at room temperature.

Lithium Superionic Conductive Nanofiber-Reinforcing High-Performance Polymer Electrolytes for Solid-State Batteries.

Although composite solid-state electrolytes (CSEs) are considered promising ionic conductors for high-energy lithium metal batteries, their unsatisfactory ionic conductivity, low mechanical strength, poor thermal stability, and narrow voltage window limit their practical applications. We have prepared a new lithium superionic conductor (Li-HA-F) with an ultralong nanofiber structure and ultrahigh room-temperature ionic conductivity (12.6 mS cm-1). When it is directly coupled with a typical poly(ethylene oxide)-based solid electrolyte, the Li-HA-F nanofibers endow the resulting CSE with high ionic conductivity (4.0 × 10-4 S cm-1 at 30 °C), large Li+ transference number (0.66), and wide voltage window (5.2 V). Detailed experiments and theoretical calculations reveal that Li-HA-F supplies continuous dual-conductive pathways and results in stable LiF-rich interfaces, leading to its excellent performance. Moreover, the Li-HA-F nanofiber-reinforced CSE exhibits good heat/flame resistance and flexibility, with a high breaking strength (9.66 MPa). As a result, the Li/Li half cells fabricated with the Li-HA-F CSE exhibit good stability over 2000 h with a high critical current density of 1.4 mA cm-2. Furthermore, the LiFePO4/Li-HA-F CSE/Li and LiNi0.8Co0.1Mn0.1O2/Li-HA-F CSE/Li solid-state batteries deliver high reversible capacities over a wide temperature range with a good cycling performance.

A Chemically Bonded Ultraconformal Layer between the Elastic Solid Electrolyte and Lithium Anode for High-performance Lithium Metal Batteries.

Although high ionic conductivities have been achieved in most solid-state electrolytes used in lithium metal batteries (LMBs), rapid and stable lithium-ion transport between solid-state electrolytes and lithium anodes remains a great challenge due to the high interfacial impedances and infinite volume changes of metallic lithium. In this work, a chemical vapor-phase fluorination approach is developed to establish a lithiophilic surface on rubber-derived electrolytes, which results in the formation of a resilient, ultrathin, and mechanically integral LiF-rich layer after electrochemical cycling. The resulting ultraconformal layer chemically connects the electrolyte and lithium anode and maintains dynamic contact during operation, thus facilitating rapid and stable lithium-ion transport across interfaces, as well as promoting uniform lithium deposition and inhibiting side reactions between electrolyte components and metallic lithium. LMBs containing the novel electrolyte have an ultralong cycling life of 2500 h and deliver a high critical current density of 1.1 mA cm-2 in lithium symmetric cells as well as showing good stability over 300 cycles in a full cell.

N,S-Doped Porous Carbon Nanobelts Embedded with MoS2 Nanosheets as a Self-Standing Host for Dendrite-Free Li Metal Anodes.

Metallic Li is one of the most promising anodes for high-energy secondary batteries. However, the enormous volume changes and severe dendrite formation during the Li plating/stripping process hinder the practical application of Li metal anodes (LMAs). We have developed a sulfate-assisted strategy to synthesize a self-standing host composed of N,S-doped porous carbon nanobelts embedded with MoS2 nanosheets (MoS2 @NSPCB) for use in LMAs. In situ measurements and theoretical calculations reveal that the uniformly distributed MoS2 derivatives within the carbon nanobelts serve as stable lithiophilic sites which effectively homogenize Li nucleation and suppress dendrite formation. In addition, the hierarchical porosity and 3D nanobelt networks ensure fast Li-ion diffusion and accommodate the volume change of Li deposits during the plating/stripping process. As a result, a Li-Li symmetric cell using the MoS2 @NSPCB host operates steadily over 1500 h with an ultralow voltage hysteresis (≈24.2 mV) at 3 mA cm-2 /3 mAh cm-2 . When paired with a LiFePO4 cathode, the current collector-free LMA endows the full cell with a high energy density of 460 Wh kg-1 and good cycling performance (with a capacity retention of ≈70% even after 1600 cycles at 10 C).

A Highly Durable Rubber-Derived Lithium-Conducting Elastomer for Lithium Metal Batteries.

Elastomers offer attractive advantages over classical solid-state electrolytes in terms of ensuring stable interfacial contact and maintaining fatigue durability, but the low ionic conductivity obstructs their practical applications in long-life lithium metal batteries. In this work, rubber-derived lithium-conducting elastomer has been developed via sulfur vulcanization of nitrile butadiene rubber with a polymerizable ionic liquid to provide both high resilience and dramatically improved ionic conductivity. Owing to the chemically crosslinked network between rubber chains and ionic liquid fragments generated during vulcanization, the elastic lithium-conductor achieves high resilience of 0.92 MJ m-3 , superior cyclic durability of 1000 cycles at 50% strain, and high room-temperature ionic conductivity of 2.7 × 10-4  S cm-1 . Consequently, the corresponding solid-state lithium/LiFePO4 battery exhibits a high capacity of ≈146 mAh g-1 with a high capacity retention of 94.3% for up to 300 cycles.

High-Entropy Atomic Layers of Transition-Metal Carbides (MXenes).

High-entropy materials (HEMs) have great potential for energy storage and conversion due to their diverse compositions, and unexpected physical and chemical features. However, high-entropy atomic layers with fully exposed active sites are difficult to synthesize since their phases are easily segregated. Here, it is demonstrated that high-entropy atomic layers of transition-metal carbide (HE-MXene) can be produced via the selective etching of novel high-entropy MAX (also termed Mn +1 AXn (n = 1, 2, 3), where M represents an early transition-metal element, A is an element mainly from groups 13-16, and X stands for C and/or N) phase (HE-MAX) (Ti1/5 V1/5 Zr1/5 Nb1/5 Ta1/5 )2 AlC, in which the five transition-metal species are homogeneously dispersed into one MX slab due to their solid-solution feature, giving rise to a stable transition-metal carbide in the atomic layers owing to the high molar configurational entropy and correspondingly low Gibbs free energy. Additionally, the resultant high-entropy MXene with distinct lattice distortions leads to high mechanical strain into the atomic layers. Moreover, the mechanical strain can efficiently guide the nucleation and uniform growth of dendrite-free lithium on HE-MXene, achieving a long cycling stability of up to 1200 h and good deep stripping-plating levels of up to 20 mAh cm-2 .

Single Zinc Atoms Immobilized on MXene (Ti3C2Clx) Layers toward Dendrite-Free Lithium Metal Anodes.

Lithium (Li) metal has been considered as one of the most prospective anodes for Li-based batteries owing to its high theoretical gravimetric capacity (3860 mAh g-1) and low potential (-3.04 V vs standard hydrogen electrode (SHE)). Unfortunately, there commonly exist uncontrollable dendrites in lithium anodes during the repeated plating-stripping processes, causing short cycle life and even short circuiting of lithium batteries. Here, single zinc atoms immobilized on MXene (Ti3C2Clx) layers (Zn-MXene) were produced to efficiently induce Li nucleation and growth. At the initial plating stage, lithium tended to nucleate homogeneously on the surface of Zn-MXene layers due to the large presence of Zn atoms and then grow vertically along the nucleated sites owing to a strong lightning rod effect at the edges, affording bowl-like lithium without lithium dendrites. Thus, a low overpotential of 11.3 ± 0.1 mV, long cyclic life (1200 h), and deep stripping-plating levels up to 40 mAh cm-2 are obtained by using Zn-MXene films as lithium anodes.

Gradient-Distributed Nucleation Seeds on Conductive Host for a Dendrite-Free and High-Rate Lithium Metal Anode.

Much attention is paid to metal lithium as a hopeful negative material for reversible batteries with a high specific capacity. Although applying 3D hosts can relieve the dendrite growth to some extent, gradient-distributed lithium ion in 3D uniform hosts still induces uncontrolled lithium dendrites growth, especially at high lithium capacity and high current density. Herein, a 3D conductive carbon nanofiber framework with gradient-distributed ZnO particles as nucleation seeds (G-CNF) to regulate lithium deposition is proposed. Based on such a unique structure, the G-CNF electrode exhibits a high average Coulombic efficiency (CE) of 98.1% for 700 cycles at 0.5 mA cm-2 . Even at 5 mA cm-2 , the G-CNF electrode performs a stable cycling process and high CE of 96.0% for over 200 cycles. When the lithium-deposited G-CNF (G-CNF-Li) anode is applied in a full cell with a commercial LiFePO4 cathode, it exhibits a stable capacity of 115 mAh g-1 and high retention of 95.7% after 300 cycles. Through inducing the gradient-distributed nucleation seeds to counter the existing Li-ion concentration polarization, a uniform and stable lithium deposition process in the 3D host is achieved even under the condition of high current density.

Graphene Oxide/Chitosan Aerogel Microspheres with Honeycomb-Cobweb and Radially Oriented Microchannel Structures for Broad-Spectrum and Rapid Adsorption of Water Contaminants.

Multifunctional graphene oxide (GO)/chitosan (CS) aerogel microspheres (GCAMs) with honeycomb-cobweb and radially oriented microchannel structures are prepared by combining electrospraying with freeze-casting to optimize adsorption performances of heavy metal ions and soluble organic pollutants. The GCAMs exhibit superior adsorption capacities of heavy metal ions of Pb(II), Cu(II), and Cr(VI), cationic dyes of methylene blue (MB) and Rhodamine B, anionic dyes of methyl orange and Eosin Y, and phenol. It takes only 5 min to reach 82 and 89% of equilibrium adsorption capacities for Cr(VI) (292.8 mg g-1) and MB (584.6 mg g-1), respectively, much shorter than the adsorption equilibrium time (75 h) of a GO/CS monolith. More importantly, the GCAMs maintain excellent adsorption capacity for six cycles of adsorption-desorption. The broad-spectrum, rapid, and reusable adsorption performance makes the GCAMs promising for highly efficient water treatments.

Electrospun polyacrylonitrile nanofibers loaded with silver nanoparticles by silver mirror reaction.

The silver mirror reaction (SMR) method was selected in this paper to modify electrospun polyacrylonitrile (PAN) nanofibers, and these nanofibers loaded with silver nanoparticles showed excellent antibacterial properties. PAN nanofibers were first pretreated in AgNO3 aqueous solution before the SMR process so that the silver nanoparticles were distributed evenly on the outer surface of the nanofibers. The final PAN nanofibers were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), TEM-selected area electron diffraction (SAED), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). SEM, TEM micrographs and SAED patterns confirmed homogeneous dispersion of the silver nanoparticles which were composed of monocrystals with diameters 20-30nm. EDS and XRD results showed that these monocrystals tended to form face-centered cubic single silver. TGA test indicated that the nanoparticles loaded on the nanofibers reached above 50wt.%. This material was also evaluated by the viable cell-counting method. The results indicated that PAN nanofibers loaded with silver nanoparticles exhibited excellent antimicrobial activities against gram-negative Escherichia coli (E. coli), gram-positive Staphylococcus aureus (S. aureus) and the fungus Monilia albicans. Thus, this material had many potential applications in biomedical fields.

[Synthesis and characterization of mixed metal oxide pigments].

In the present work, aluminum chloride and various soluble salts of doping ions were dissolved in water. In addition, urea and polyvinyl pyrrolidone (PVP) were also dissolved in the above aqueous solution under supersonic treatments. Then the solutions were heated to induce the hydrolysis of urea so that soluble aluminum and doping ions convert into insoluble hydroxide or carbonate gels. After calcinations, the obtained gels change to mixed metal oxide pigments whose color is related to type and concentrations of the doping ions. XRD characterization demonstrates that the diffraction patterns of the products are the same as that of alpha-alumina. Diffuse reflectance spectra of samples of the samples in UV-Vis regions show that the absorption bands for d-d transitions of the doping ions undergo considerable change as the coordinate environments change. In addition, L*, a* and b* values of the pigments were measured by using UV-Vis densitometer. SEM results indicate that the size of the pigment powders is in the range 200-300 nm. The pigments are quite stable since no evidence of dissolution was observed after the synthesized pigment is soaked for 24 hours. ICP test shows that very little amount of doped metal occurs in the corresponding filtrate. The above results suggest that these new kinds of mixed metal oxide pigments are stable, non-toxic, environmental friendly and they may be applicable in molten spinning process and provide a new chance for non-aqueous printing and dyeing industry.