Amphiphilic diblock copolymer-mediated structure control in nanoporous germanium-based thin films

Dendritic Copper Current Collectors as a Capacity Boosting Material for Polymer-Templated Si/Ge/C Anodes in Li-Ion Batteries

Dendritic copper offers a highly effective method for synthesizing porous copper anodes due to its intricate branching structure. This morphology results in an elevated surface area-to-volume ratio, facilitating shortened electron pathways during aqueous and electrolyte permeation. Here, we demonstrate a procedure for a time- and cost-efficient synthesis routine of fern-like copper microstructures as a host for polymer-templated Si/Ge/C thin films. Dissolvable Zintl clusters and sol-gel chemistry are used to synthesize nanoporous coating as the anode. Cyclic voltammetry (CV) with KOH as the electrolyte is used to estimate the surface area increase in the dendritic copper current collectors (CCs). Half cells are assembled and tested with battery-related techniques such as CV, galvanostatic cycling, and electrochemical impedance spectroscopy, showing a capacity increase in the dendritic copper cells. Energy-dispersive X-ray spectroscopy is used to estimate the removal of K in the bulk after oxidizing the Zintl phase K12Si8Ge9 in the polymer/precursor blend with SiCl4. Furthermore, scanning electron microscopy images are provided to depict the thin films after synthesis and track the degradation of the half cells after cycling, revealing that the morphological degradation through alloying/dealloying is reduced for the dendritic Cu CC anodes as compared with the bare reference. Finally, we highlight this time- and cost-efficient routine for synthesizing this capacity-boosting material for low-mobility and high-capacity anode coatings.

SiBCN ceramic precursor modified phthalonitrile resin with high thermal resistance

In order to expand the application of phenolic-type phthalonitrile resin in high-temperature fields, a series of organic–inorganic hybrid materials have been prepared via conventional blending and doping method. The chemical transformations were monitored by various measurements, while the curing behavior was evaluated by differential scanning calorimetry (DSC), and these new blends could be also cured under auto-catalytic process. The onset polymerization exothermic temperature shifted to lower temperatures (195.3°C). Later, the compatibility within the cured products was analyzed by using energy dispersive spectrometer (EDS) and scanning electron microscope (SEM), where no phase separation occurred between the ceramic domain and the phthalonitrile polymer. Upon curing, the thermal properties of the polymers were characterized by dynamic thermomechanical analysis (DMA) and thermogravimetric analysis (TGA), where enhanced heat resistance and thermal stability were discovered, The blends residual weight (Cy) value was 57.6% with 15 wt.% SiBCN at 1000°C. And when blended with SiBCN precursor, no peak or onset point could be observed in the temperature range (50 to 500°C), which indicated the glass transition temperature greater than 500°C. Additionally, the dielectric properties were evaluated. And when the content was 5 wt.%, the blends dielectric loss was 0.0043 and the permittivity was 4.31. The above results indicated that the introduction of ceramic precursors could enhance the thermal performance of phthalonitrile polymers, consequently the hybrid materials shown great potential in the application of higher temperature fields.

Mesoporous GeOx/Ge/C as a Highly Reversible Anode Material with High Specific Capacity for Lithium-Ion Batteries

Nanostructured Ge is considered a highly promising material for Li-ion battery applications as Ge offers high specific capacity and Li-ion diffusivity, while inherent mesoporous nanostructures can contribute resistance against capacity fading as typically induced by high volume expansion in bulk Ge films. Mesoporous GeO_x/Ge/C films are synthesized using K₄Ge₉ Zintl clusters as a Ge precursor and the amphiphilic diblock copolymer polystyrene-block-polyethylene oxide as a templating tool. As compared to a reference sample without post-treatment, enhanced surface-to-volume ratios are achieved through post-treatment with a poor-good azeotrope solvent mixture. High capacities of over 2000 mA h g^-1 are obtained with good stability over 300 cycles. Information from morphological and compositional characterization for both reference and post-treated sample suggests that the good electrochemical performance originates from reversible GeO₂ conversion reactions.

Giant surfactant-stabilized N2-foam for enhanced oil recovery after water flooding

A novel giant surfactant, APOSS-PS₅₀, possessing good surface activity, and viscosifying and reinforcing ability as a foam stabilizer, was synthesized successfully to enhance the physical properties of foaming solutions and foam. APOSS-PS₅₀ was widely distributed at the foam gas–liquid interface and adjacent liquid layers through diffusion and adsorption, obviously decreasing the surface tension and improving the foamability and stability of the foam. Furthermore, the aggregation of APOSS-PS₅₀ in the foam films resulted in the formation of a self-assembled nano-sized network through supramolecular interactions (such as hydrogen bonding, π–π stacking, and van der Waals attraction), thus increasing the foam viscoelasticity, including its interfacial viscoelastic modulus and apparent viscosity. Meanwhile, from the sandpack flooding experiments, compared with HPAM/AOS (HPAM: partially hydrolyzed acrylamide and AOS: alpha olefin sulfonate), the differential pressure and final oil recovery after APOSS-PS₅₀/AOS foam flooding increased by 23.5% and 23.2%, up to 2.68 MPa and 81.7%, respectively. In general, APOSS-PS₅₀ significantly promoted the plugging, profile control and oil displacement performance of foam.

A giant surfactant with high surface activity and strong viscosifying ability was prepared through a facile one-pot procedure for foam stabilization in EOR projects.