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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.

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At least 1,045 records · Page 58
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Synthesis of Self-Assembled rGO-Co{sub 3}O{sub 4} Nanoparticles in Nanorods Structure for Supercapacitor Application

A simple hydrothermal process was used to design self-assembled Co{sub 3}O{sub 4} nanoparticles in nanorod structure in the presence of graphene oxide as a template. The as-prepared Co{sub 3}O{sub 4} sample in a loose powder form was calcined at 450 °C to get the well-crystalline phase of the same compound. The obtained Co{sub 3}O{sub 4} powder sample was characterized by using the powder XRD and SEM. The XRD pattern shows totally nine distinct reflection peaks of (111), (220), (311), (222), (400), (422), (511), (440), and (533) planes. The most intense peaks were chosen to evaluate the structural parameters. The lattice parameters (a), volume (V), and density (ρ) of the samples are 8.09 Å, 529.47 Å{sup 3}, 6.06 g/cc, which are comparable to the value of lattice parameter (a = 8.056 Å), volume (V = 528.30 Å{sup 3}), and density (ρ = 6.055 gm/cc) for bulk Co{sub 3}O{sub 4}. The average size of the Co{sub 3}O{sub 4} nanoparticles is 14 nm which is smaller than the SEM size of 50 nm corresponding to the agglomeration of tiny particles. Further, the formation of Co{sub 3}O{sub 4} nanoparticles were also confirmed by obtaining the band at 569, 1334,1337, 1566, and 3397 cm{sup −1} in FTIR spectrum. Totally five characteristics peaks from Co{sub 3}O{sub 4} at 182.57, 456.49, 505.84, 605.80, and 618.02 cm{sup −1} and peaks from GO-Co{sub 3}O{sub 4} at 182.57, 483.44, 505.84, 605.80, and 618.02 cm{sup −1} corresponding to F{sub 2g}, E{sub g}, F{sub 2g}, F{sub 2g,} and A{sub g} modes of the crystalline Co{sub 3}O{sub 4}, respectively, in the Raman spectra. In the case of GO-Co{sub 3}O{sub 4} composite, low-intensity peaks of D and G bands are observed. The specific capacitance in rGO-Co{sub 3}O{sub 4} nanocomposite is about 65.15 Fg{sup −1}.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Construction of Ni-Co-Mn layered double hydroxide nanoflakes assembled hollow nanocages from bimetallic imidazolate frameworks for supercapacitors

Highlights: • Bimetallic Co-Mn ZIF is successfully prepared. • N-Co-Mn LDH nanoflakes assembled hollow nanocage is constructed by a MOF templating method. • The N-Co-Mn LDH exhibits excellent pseudocapacitive performance. - Abstract: Layered double hydroxides (LDHs) with 3-dimentional (3D) hollow nanoarchitetures are highly desirable for energy related applications. In this study, Ni-Co-Mn LDH nanoflakes assembled hollow nanocages are constructed from bimetallic imidazolate framworks precursors. Benefiting from the 3D hierarchical porous strcuture and composition, the as-synthesized ternary Ni-Co-Mn LDH hollow nanocage, as a electrode for supercapacitor, demonstrates a remarkable electrochemical performance with a high specific capacitance of 2012.5 F g{sup −1} at 1 A g{sup −1} and a good rate capacity of 75.0% retention at 10 A g{sup −1}, significantly outperforming binary Ni-Co LDH (1266.2 F g{sup −1} at 1 A g{sup −1}, 41.8% retention at 10 A g{sup −1}). This work demonstrates the construction of 3D hollow nanostructured LDH with multicomponent compositions for the first time, and can be simply extended to construct other hollow structured electrode materials for energy storage devices.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

A New Hybrid Material: Monolithic Biomorphic Carbon/Nickel Nanoparticles for Energy Storage Devices

A simple, inexpensive, and ecologically safe method has been used to obtain a new hybrid material—biomorphic carbon/nickel nanoparticles (bioC/NiNPs) composite—comprising a highly porous, partly graphitized carbon matrix (bioC) containing uniformly distributed nickel nanoparticles (NiNPs) with 5–70 nm dimensions. Transmission electron microscopy investigation showed that the bioC matrix consists predominantly of onion-like carbon with hollow capsules/pores about 5 nm in size and also contains graphite globules with dimensions up to 200 nm. The obtained bioC/NiNPs composite demonstrates high electrochemical capacitance stable up to about 1000 charge/discharge cycles and can be considered as promising material for monolithic electrodes of supercapacitors.

25 ENERGY STORAGE↗
DOE OSTI2023

Dynamic Stabilization of Metastable States in Triple-Well Ferroelectric Sn 2 P 2 S 6

Polarization dynamics in ferroelectric materials is governed by the effective potential energy landscape of the order parameter. The unique aspect of ferroelectrics compared to many other transitions is the possibility of more than two potential wells, leading to complicated energy landscapes with new fundamental and functional properties. In this work, direct dynamic evidence is revealed of a triple-well potential in the metal thiophosphate Sn 2 P 2 S 6 compound using multivariate scanning probe microscopy combined with theoretical simulations. The key finding is that the metastable zero polarization state can be accessed through a gradual switching process and is stabilized over a broad range of electric fields. Simulations confirm that the observed zero polarization state originates from a kinetic stabilization of the nonpolar state of the triple-well, as opposed to domain walls. Dynamically, the triple-well of Sn 2 P 2 S 6 becomes equivalent to antiferroelectric hysteresis loops. Therefore, this material combines the robust and well-defined domain structure of a proper ferroelectric with dynamic hysteresis loops present in antiferroelectrics. Moreover, the triple-well enhances mem-capacitive effects in Sn 2 P 2 S 6 , which are forbidden for ideal double-well ferroelectrics. These findings provide a path to tunable electronic elements for beyond binary high-density computing devices and neuromorphic circuits based on dynamic properties of the triple-well.

36 MATERIALS SCIENCE↗
DOE OSTI2022

High Velocity, Low‐Voltage Collective In‐Plane Switching in (100) BaTiO 3 Thin Films

Abstract Ferroelectrics are being increasingly called upon for electronic devices in extreme environments. Device performance and energy efficiency is highly correlated to clock frequency, operational voltage, and resistive loss. To increase performance it is common to engineer ferroelectric domain structure with highly‐correlated electrical and elastic coupling that elicit fast and efficient collective switching. Designing domain structures with advantageous properties is difficult because the mechanisms involved in collective switching are poorly understood and difficult to investigate. Collective switching is a hierarchical process where the nano‐ and mesoscale responses control the macroscopic properties. Using chemical solution synthesis, epitaxially nearly‐relaxed (100) BaTiO 3 films are synthesized. Thermal strain induces a strongly‐correlated domain structure with alternating domains of polarization along the [010] and [001] in‐plane axes and 90° domain walls along the [011] or [01] directions. Simultaneous capacitance–voltage measurements and band‐excitation piezoresponse force microscopy revealed strong collective switching behavior. Using a deep convolutional autoencoder, hierarchical switching is automatically tracked and the switching pathway is identified. The collective switching velocities are calculated to be ≈500 cm s −1 at 5 V (7 kV cm −1 ), orders‐of‐magnitude faster than expected. These combinations of properties are promising for high‐speed tunable dielectrics and low‐voltage ferroelectric memories and logic.

36 MATERIALS SCIENCE↗
DOE OSTI2024

3D Ferroelectric Phase Field Simulations of Polycrystalline Multi‐Phase Hafnia and Zirconia Based Ultra‐Thin Films

Abstract HfO 2 – and ZrO 2 –based ferroelectric thin films have emerged as promising candidates for the gate oxides of next‐generation electronic devices. Recent work has experimentally demonstrated that a tetragonal/orthorhombic (t/o‐) phase mixture with partially in‐plane polarization can lead to negative capacitance (NC) stabilization. However, there is a discrepancy between experiments and the theoretical understanding of domain formation and domain wall motion in these multi‐phase, polycrystalline materials. Furthermore, the effect of anisotropic domain wall coupling on NC has not been studied so far. Here, 3D phase field simulations of HfO 2 – and ZrO 2 –based mixed‐phase ultra‐thin films on silicon are applied to understand the necessary and beneficial conditions for NC stabilization. It is found that smaller ferroelectric grains and a larger angle of the polar axis with respect to the out‐of‐plane direction enhances the NC effect. Furthermore, it is shown that theoretically predicted negative domain wall coupling even along only one axis prevents NC stabilization. Therefore, it is concluded that topological domain walls play a critical role in experimentally observed NC phenomena in HfO 2 – and ZrO 2 –based ferroelectrics.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2021

Signal Origin of Electrochemical Strain Microscopy and Link to Local Chemical Distribution in Solid State Electrolytes

Electrochemical strain microscopy (ESM) is a distinguished method to characterize Li-ion mobility in energy materials with extremely high spatial resolution. The exact origin of the cantilever deflection when the technique is applied on solid state electrolytes (SSEs) is currently discussed in the literature. Under-standing local properties and influences on ion mobility in SSEs is of utmost importance to improve such materials for next generation batteries. Here, the exact signal formation process of ESM when applied on sodium super ionic conductor (NASICON)-type SSE containing Na- and Li-ions is investigated. Changes in the dielectric properties, which are linked to the local chemical composition, are found to be responsible for the observed contrast in the deflection of the cantilever instead of a physical volume change as a result of Vegard´s Law. The cantilever response is strongly reduced in areas of high sodium content which is attributed to a reduction of the tip-sample capacitance in comparison to areas with high lithium content. This is the first time a direct link between electrostatic forces in contact mode and local chemical information is demonstrated on SSEs. Furthermore, the results open up new possibilities in information gain since dielectric proper-ties are sensitive to subtle changes in local chemical composition.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Design of Near Infrared and Visible Kinetic Inductance Detectors Using MIM Capacitors

We are developing superconducting Microwave Kinetic Inductance Detectors to operate at near infrared and optical wavelengths for astronomy. In order to efficiently meet with the requirements of astronomical applications, we propose to replace the interdigitated capacitor by a metal–insulator–metal capacitor which has the advantage of presenting a larger capacitance value within a much smaller space. The pixel will occupy a space of typically 100 × 85 µm which is nine times less than a typical pixel size using the interdigitated capacitor operating at the same frequency, below 2 GHz.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Impedance Spectroscopy, Magnetic and Optical Analysis of Cadmium Tungstate Nanoparticles from Influence of Capping Agent Additives

Nano crystals of cadmium tungstate (CdWO{sub 4}) were obtained by facile precipitation route by using cadmium sulfate octahydrate and sodium tungstate dihydrate. These nanoparticles were then coated using different capping agents such as glucose, polyvinyl alcohol (PVA), and valine and their effects on the particle size, band gap, morphology, and magnetic character were investigated by powder X-ray diffraction, UV-Visible, FESEM, TEM, and VSM analysis. Capping agents are used in the synthesis of nanoparticles since they facilitate the growth and aggregation of particles in a precise manner, by usually acting as a physical barrier which controls the flow of free electron to the catalyst, so that they can be utilized by the catalyst and sensors of nanoparticle. Impedance spectroscopic technique was carried out, which was very useful in separating the grain boundary resistance and grain boundary capacitance contributions. We discuss the utilization of capping agents and their effects, including surface, optical and intergranular potential barriers in this work.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Influence of Annealing on Microstructure, Electrochemical, and Magnetic Properties of Co-Doped SrTiO{sub 3} Nanocubes

Effect of annealing on microstructure, electrochemical, and magnetic properties of Co-doped SrTiO{sub 3} nanocubes obtained by the hydrothermal method was studied. X-ray diffraction (XRD) results of all as-prepared and annealed Co-doped SrTiO{sub 3} samples revealed a cubic perovskite structure with the second phases of SrCO{sub 3} and Co{sub 3}O{sub 4}in as-prepared and annealed SrTi{sub 0.90}Co{sub 0.10}O{sub 3} samples, respectively. Agglomerated nanocubes could be clearly observed in all as-prepared and annealed Co-doped samples by scanning electron microscope (SEM) and transmission electron microscope (TEM). X-ray absorption near edge spectroscopy (XANES) results suggested the presence of Co{sup 2+} cations in as-prepared Co-doped SrTiO{sub 3} samples, while both of Co{sup 2+} and Co{sup 3+} cations were found in annealed Co-doped SrTiO{sub 3} samples. The cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) results of as-prepared and annealed SrTi{sub 1-x}Co{sub x}O{sub 3} (x = 0.05, 0.075 and 0.10) electrodes revealed pseudocapacitor behavior of the Faradaic redox reaction type. The specific capacitance (Csc) was affected by the increase of Co content in all as-prepared and annealed Co-doped SrTiO{sub 3} samples with an excellent cycling stability after 200 cycle test of 97.24% and the highest value of 75.28 F g{sup −1} at 1 A g{sup −1} in an annealed SrTi{sub 0.925}Co{sub 0.075}O{sub 3} electrode. Magnetization measurements at room temperature using vibrating sample magnetometer (VSM) revealed diamagnetic behavior of as-prepared SrTiO{sub 3} sample, whereas paramagnetic behavior was observed in all as-prepared Co-doped SrTiO{sub 3} samples. After annealing, undoped sample exhibited paramagnetic behavior, whereas ferromagnetic behavior was observed in all Co-doped SrTiO{sub 3} samples with the increase of saturation magnetization (M{sub s}) at 10 kOe from 0.58 to 1.63 emu/g and the coercive field (H{sub c}) from 43.71 to 123.87 Oe, suggested to originate from the face-center exchange (FCE) mechanism.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Structural, Magnetic, and Giant Dielectric Properties of Gd Substituted CuFeO{sub 2} Composites

To study the effects of structural modulation by doping rare earth element on the magnetic and dielectric properties, CuFe{sub 1-x}Gd{sub x}O{sub 2} (0 ≤ x ≤ 0.2) samples are synthesized using the solid-state reaction method. The XRD and SEM results show that a small amount of Gd{sup 3+} ions (x ≤ 0.07) effectively occupies the Fe{sup 3+} site and promotes the grain growth of the CuFeO{sub 2} system. Judging from the magnetic property measurements, the samples (x = 0, 0.01) undergo two successive magnetic transitions. Further increase of x, the magnetic transition of the samples (x ≥ 0.07) has not been detected in the testing temperature range. The magnetization hysteresis loops show that all of the samples have weak ferromagnetic properties, and the saturation magnetization is obviously enhanced with increasing x. Most interestingly, the dielectric measurements suggests that CuFeO{sub 2} samples exhibit a giant dielectric constant (ε{sub γ}~10{sup 4}), and ε{sub γ} is obviously improved (~ 4.0 × 10{sup 4}) using the proper Gd content. The dielectric properties are explained using the internal barrier layer capacitance model (IBLC).

36 MATERIALS SCIENCE↗
DOE OSTI2018

A computationally efficient method for tempered fractional differential equations with application

This paper investigates the numerical approximation of the tempered fractional integral by using the Sinc-collocation scheme. The algorithm is extended to solve a class of tempered fractional differential equations that converges to the solution with exponential rate. Several numerical examples compare the numerical approximations with the exact solutions. The behavioral responses of the lumped capacitance model with tempered fractional order for transient conduction are investigated. The efficiency and accuracy of the proposed scheme are analyzed in the perspective of the L{sub 2}-norm error and convergence order.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2024

Refining water and carbon fluxes modeling in terrestrial ecosystems via plant hydraulics integration

Plant hydraulics substantially affects terrestrial water and carbon cycles by modulating water transport and carbon assimilation. Despite improved drought simulations in certain ecosystems through their integration into land surface models (LSMs), the broader application of plant hydraulics in diverse ecosystems and hydroclimates is still underexplored. Here, in this study, we implemented the recently developed Noah-Multiparameterization Land Surface Model (Noah-MP LSM) equipped with a plant hydraulics scheme (Noah-MP-PHS) across 40 FLUXNET sites globally. Employing the Shuffled Complex Evolution-University of Arizona (SCE-UA) auto-calibration algorithm, we optimized key plant hydraulics parameters for these sites spanning eight vegetation types in both arid and humid climates. Noah-MP-PHS significantly improves the simulation of evapotranspiration (ET) and gross primary production (GPP) by better representing atmospheric and soil water stress compared to traditional soil hydraulic schemes (SHSs, such as Noah and CLM). The augmented Noah-MP-PHS models reduce surface flux overestimation and underestimation, exhibiting an average increase of 0.14 and 0.15 in Kling-Gupta Efficiency (KGE) compared to Noah and CLM, respectively. The explicit consideration of plant capacitance in PHS reveals substantial deep-layer and nocturnal root water uptake especially under dry conditions. We employed eXplainable Machine learning (XML) to quantify the model’s relative sensitivity to newly introduced leaf-, stem and root-related parameters in PHS. The sensitivity analysis reveals a rise in root parameter importance and a decline in leaf and stem parameters as conditions shift from humid to arid. These findings indicate that as aridity states vary, the most influential parameters affecting surface fluxes variation may change in parameter calibration for PHS applications. Our findings underscore the importance of incorporating plant hydraulics into LSMs to enhance simulations of terrestrial water and carbon dynamics. These findings are crucial for understanding ecosystem responses to global climate changes and guide the broader application of PHS at larger scales.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

Thermoelectric heating and cooling–integrated dishwasher with thermal energy storage

Household dishwashers must address several performance goals: maximize washing and drying performance, while minimizing cycle duration, energy consumption, and water consumption. This study develops and examines a novel thermoelectric heating and cooling (TEHC) system with thermal energy storage applied to a household dishwasher (DW), aiming to improve the energy and drying performance of a commercially-available dishwasher while maintaining its washing performance, water consumption, and cycle duration. Experimental testing conducted on the novel TEHC-DW system demonstrates an 8.7% reduction in total energy consumption, lowering the per-cycle usage to 0.952 kWh, and a 40% reduction in energy consumption for internal water heating. The novel TEHC-DW system also demonstrates better drying performance, shortening the drying time by 42% to reach the same remaining moisture content as a commercially-available system. In addition, a resistance-capacitance network model is developed that predicts total drying time, total energy consumption, and the highest temperature reached in the tub (53.4 °C). The model accuracy is validated with experimental data (within ±1 K), and the model functions as a design tool via a parametric study to evaluate the next-generation design and the effect of the number of thermoelectric modules and thermoelectric driving force (i.e., current). Overall, this study demonstrates the potential for TEHC technology to improve energy efficiency and drying performance in household dishwashers.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

A simple centrifuge cell method for ex situ quantification of electrical conductivity of slurry electrode materials

We present the design, experimental procedure, and experimental evaluation of a system for fast, simple, and ex situ characterization of electrical conductivity of slurry electrode materials. The system uses a custom-designed electrochemical cell compatible with centrifugation in a swing-bucket centrifuge. The cell features cylindrical graphite electrodes that are partially sheathed so as to expose only 2 mm of the electrode surface to the bottom region of the packed particulate pellet. Also presented is a conduction model that provides a shape factor for estimating effective conductivity. We tested aqueous solutions of carbon black (CB), activated carbon (AC), and mixtures thereof. These particles were dispersed in 0.0 and 0.5 M NaCl solutions. Measurements show that the effective conductivity initially increases linearly with pellet mass and then saturates at higher masses. Notably, CB exhibited a fivefold increase in conductivity than AC at equal pellet masses. CB/AC mixtures at a fixed pellet mass were tested with CB mass fractions of 0 to 100%. Interestingly, the mixture conductivity was found to be a non-monotonic function of CB mass fraction, with a maximum conductivity at about 60 % CB mass fraction. At this maximum, the mixture conductivity is approximately 30 % higher than pure CB. NaCl concentration in the slurry solution had no effects on conductivity. These results highlight the interactions between slurry electrode composition and compaction, offering insights for optimizing slurry electrodes. Furthermore, the system and results may also be applicable to evaluation of particulate materials (including slurries) used for Li-ion batteries, capacitive deionization, fuel cells, and flow electrodes.

Capacitive deionization↗
DOE OSTI2024

Selective pseudocapacitive immobilization of REE elements on carbon based electrodes

Current extraction technologies for rare earth elements at ambient conditions are reagent and energy intensive, giving rise to significant quantities of secondary waste streams. Exploration of the removal of common cations from aqueous streams has been undertaken with carbon materials and have shown promising results. However, those promising materials have not been explored extensively for rare earth element capture from aqueous process streams. In this study, a carbon electrode was investigated for the adsorption and immobilization of REE elements from aqueous solutions. Cyclic voltammetry studies of the carbon electrode displayed a pseudocapacitive behavior where it was verified that cation adsorption is accompanied by an electron transfer process. Preliminary tests showed that a current density of 89.1 mA. g -1 , allowed for the pseudocapacitive adsorption (PSA) of Nd 3+ cation without the formation of rare earth hydroxides. Hence, the selective PSA of Nd 3+ was verified in an electrolyte solution with equimolar concentrations of Nd 3+ , Mg 2+ , Li + , Na + and K + , achieving separation factors of 8.6, 1.1, and 10.9 for Nd 3+ /Li + , Nd 3+ /Na + , and Nd 3+ /Mg 2+ , respectively. Analysis of the potential-time curves for the various cations suggests that storage of ions in the electrode involved pore-spacings rather than interlayer spacings and was corroborated by XRD analysis. Specific capacitance as high as >640 F.g -1 for Nd 3+ was also observed for the carbon electrode, with Faradaic efficiencies (FE) of > 20% for Nd 3+ and Mg 2+ , and > 9% for Na + . Furthermore, adsorption capacity of >125 mg g -1 after 4hrs of electrosorption was observed for Nd 3+ . In the presence of the Nd 3+ electrolyte, the electrode achieved increasing storage of Nd 3+ with >94% retention of Nd 3+ with a FE > 20% over 6 cycles between loading and releases in 1 M KCl solution. In conclusion, these preliminary results provide information and some guidance on the selective recovery of rare earth elements, such as Nd, in aqueous streams in the presence of competitive cations employing the use of carbon-based materials.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2026

An approach for fast and accurate simulation of phase change material based thermal energy storage in buildings

Latent heat thermal energy storage (LHTES) has significant potential for mitigating peak electricity demand and enabling load shifting in buildings. Phase Change Material embedded heat exchangers (PCM-HX) can significantly improve energy demand management due to high storage capacity. However, PCM-HX evaluation typically depends on computationally expensive fully transient simulations, posing significant challenges for scalable system- and building-level energy assessments across different climates and system architectures. This paper presents a generalized, accurate, and computationally efficient methodology for simulating building energy systems integrated with LHTES. The PCM-HX transient performance is represented by performance maps generated using a Generalized Resistance-Capacitance Model (GRCM) that enables accurate predictions of arbitrary PCM-HXs at low computational cost. The feasibility of the proposed approach was verified using a case study considering a dual-mode heat pump-thermal energy storage (HP-TES) system simulated in Modelica with Spawn of EnergyPlus™ for a DOE prototype small office building in two locations: Tampa, FL, and International Falls, MN. The PCM-HX performance maps provided accurate predictions of PCM-HX transient behavior, with mean absolute percentage deviations within 2–4% compared to GRCM while also achieving at least 1800× reduction in computational time. Moreover, the HP-TES system achieved energy savings of up to 17.4% in Tampa, FL, and 62.2% in International Falls, MN, demonstrating the broader applicability of the proposed methodology across different climate zones. This work highlights the importance of robust PCM-HX models in enabling accurate and computationally efficient building-level simulations and enabling future research opportunities for investigating optimized HP-TES designs and advanced control strategies for grid-interactive buildings.

Modelica↗
DOE OSTI2022

Electrically regenerated ion-exchange technology: Leveraging faradaic reactions and assessing the effect of co-ion sorption

Capacitive deionization (CDI) technologies have the potential to become cost-competitive alternatives to reverse osmosis for the treatment of brackish waters. In this study, we describe our findings on the effect of co-ion sorption and faradaic side reactions on our ion exchange resin functionalized desalination electrodes which passively capture salt and reject it upon charging. This system, which we previously reported on and refer to as electrically regenerated ion exchange (ERI), avoids the use of expensive ion exchange membranes in an effort to save costs. Surprisingly, we find that, compared to a reference CDI system, ERI electrodes capture salt most effectively at low applied voltages (0.5 mg/cm 3 at 0.8 V). Both CDI and ERI systems also seem to suffer from co-ion sorption effects which negatively impact salt adsorption. However, Faradaic side reactions at higher voltages (1 V and 1.2 V) which we track via pH measurements, serve as a detriment to CDI but seem to facilitate the functionality of ERI.

42 ENGINEERING↗