Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Xerogel”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

7 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Enhanced electrochemical performance and extended cycling of resorcinol-formaldehyde derived N-doped carbon xerogel for alkali metal-ion (Li/Na/K) batteries

Resorcinol formaldehyde-derived carbon xerogel (RFC) is a versatile material with tuneable properties, synthesized through a simple sol-gel method. This study presents nitrogen-doped RF carbon xerogel (N-RFC) with 11.8 at% nitrogen doping, offering a microporous architecture ideal for alkali metal-ion (Li, Na, K) batteries. The porous N-doped framework enhances electrochemical performance by improving ion transport, increasing active storage sites, and significantly boosting metal-ion adsorption, particularly through pyrrolic nitrogen, as revealed by first-principles calculations supported by XPS analysis. N-RFC anodes showed excellent cycling stability, high-capacity retention, and fast charge/discharge capabilities, rendering them suitable for commercial applications. Notably, the N-RFC anode demonstrates high-rate long-term cycling stability, retaining its capacity of 83.5 % (188 mAh/g at 2 C-rate) and 50 % (133 mAh/g at 1250 mA/g) over 1000 cycles for Li and Na-ion batteries, respectively, favorable for commercial battery applications. Additionally, N-RFC demonstrates a reversible capacity of 120 mAh/g after 394 cycles with a retention of 82 % for K-ion batteries. The ability of the material to accommodate larger ions like Na + and K + further emphasizes its versatility and potential application in diverse alkali metal-ion battery systems.

25 ENERGY STORAGE↗
DOE OSTI2025

Xerogel-Derived Ni Electrocatalysts for the Hydrogen Evolution Reaction in Alkaline Media

Anion exchange membrane water electrolyzers (AEMWEs) represent a promising technology for hydrogen production. The big advantage of the technology is that it allows for the use of platinum group metal-free (PGM-free) electrocatalysts at both electrodes, including catalysts for the hydrogen evolution reaction (HER) at the cathode. In addition to fulfilling the cost requirement, PGM-free HER catalysts need to meet the activity and durability targets of the AEMWEs. Here, in this work, we developed several carbon-supported, xerogel-derived nickel (Ni) HER electrocatalysts and evaluated the effect of various synthesis conditions, such as the type of carbon support, Ni-to-carbon ratio, and heat-treatment temperature and time, on their performance. Scanning transmission electron microscopy combined with energy-dispersive X-ray spectroscopy (STEM-EDS), X-ray diffraction spectroscopy (XRD), and X-ray photoelectron spectroscopy (XPS) revealed the formation of Ni nanoparticles with an oxygen-rich layer on the outside. Durability of the best-performing catalyst was assessed via a constant-current hold at 10 mA cm –2 over 100 h. This catalyst was found to be more active and durable than the reference PGM-free material, a commercial Ni catalyst supported on a Vulcan XC-72. The catalyst was also tested in the cathode of a fully PGM-free AEMWE, allowing to reach 1.90 V (1.84 V HFR-free) at 1 A cm –2 at 80 °C.

08 HYDROGEN↗
DOE OSTI2023

Flame retardant biogenic building insulation materials from hemp fiber

Biogenic thermal insulation materials are in high demand because of its carbon-sequestration nature. However, high flammability, moisture condensation, and relatively high thermal conductivity of biogenic material are major concerns for sustainable building applications. In this study, we report the fire-retardant cellulose xerogel insulation nanocomposites derived from hemp fiber recycling and silica xerogel, in which the boric acid treatment improves its fire retardancy. The as-prepared materials show a low thermal conductivity of 31.3 mW/m K, high flexural modulus of 665 MPa, hydrophobicity with the water contact angle of 115°, and fire retardancy with 30% weight loss over a period of burning time 10 min. Overall, this work provides an effective method for the synthesis of fire-retardant biogenic thermal insulation materials and shows a promising way for next-generation bio-based insulation materials.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Selective Sorbent Design: CaS Aerogel for Rapid Remediation of Aqueous Pb (II)

Heavy metals are a persistent environmental problem due to their high toxicity, even at very low concentrations (parts per billion, ppb). The removal of such diluted heavy metals is challenging because of the competition the counterions (Ca 2+ , Na + , Mg 2+ , etc.) present in natural water bodies. The design of sorbents capable of removing ions below the action limit (15 ppb for Pb 2+ ) requires a strong driving force for selective uptake and rapid removal. In this work, we report the synthesis of porous CaS aerogels (surface area = 143.6 m 2 /g) by oxidative assembly of CaS nanoparticles and describe their use in selective Pb 2+ ion remediation from water. Despite the presence of amorphous CaCO 3 (up to 50 wt %) in the gel network, the gels demonstrated a capacity of 17.1 mmol Pb/g aerogel (3543 mg/g), and this could be augmented to 22.5 mmol Pb/g aerogel (4593 mg/g) by modifying the synthesis to reduce CaCO 3 content to ca. 15 wt %. Moreover, the selectivity of CaS aerogels toward Pb 2+ ions is high, as evidenced by little-to-no change in the distribution constant (K d ∼ 10 4 ) in the presence of competing ions (1 M) such as Na + , Mg 2+ , and Ca 2+ . During remediation with low concentrations (100 ppb) of Pb 2+ with CaS aerogels, the level of Pb 2+ dropped to 5.4 ppb (below the 15 ppb EPA limit) within 1 h with a 95.4% removal efficiency. In contrast to the CO 2 supercritically dried aerogels, lower surface area ambient dried gels (xerogels) only remove 40% of the lead ions from a 100 ppb solution, saturating within 1 h. The efficiency and rapidity of selective Pb 2+ uptake using CdS aerogels arise from a combination of a strong thermodynamic driving force for cation exchange (K eq = 2.5 × 10 27 ) and chemisorption along with favorable kinetics associated with the high surface area porous architecture. These results show that formation of high surface area metal chalcogenide aerogels by oxidative assembly to form nanocrystalline architectures, as previously demonstrated for II−VI and IV−VI semiconductors, can be extended to the more highly ionic alkaline earth sulfides.

Aerogels↗
DOE OSTI2024

Cellulosic gels, films and composites including the gels, and methods of forming same

Disclosed are cellulose-based 5 flexible aerogels and xerogels containing bacterial cellulose nanorods, ribbons, fibers, and the like, wherein the gels have tunable optical, heat transfer, and stiffness properties. Further disclosed are highly transparent and flexible cellulose nanofiber-polysiloxane composite aerogels featuring enhanced mechanical robustness, tunable optical anisotropy, and low thermal conductivity.

Smalyukh, Ivan I.↗