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1. Salt Hydrate Thermochemical Energy Storage in Buildings: Analyzing Storage Density and Thermal Power Output

   https://doi.org/10.1115/ES2023-106917  

   Barbosa, Erik J.; Menon, Akanksha K. (July 2023, Proceedings of the ASME 2023 17th International Conference on Energy Sustainability collocated with the ASME 2023 Heat Transfer Summer Conference)

   Thermochemical energy storage is promising for building applications as it offers high energy density and near-lossless storage. For example, inorganic salt hydrates that undergo reversible solid-gas thermochemical reactions can be used for thermal load shifting and/or shedding in buildings. However, this technology is still in early stages of development and drawbacks need to be addressed to make such a thermal battery viable. As salt hydrates differ in their morphology, crystal and/or particle size, and hygrothermal stability, it is critical to characterize thermochemical reactions accurately under specific operating conditions. Not only is the amount of heat delivered important, but so is the rate at which this heat is extracted for thermal end-use in buildings. However, the latter is not well reported in the literature, which is largely focused on energy storage rather than power density during the hydration reaction (battery discharge). To address this gap and the lack of standardized measurement methods, this work lays out a systematic simultaneous thermal analysis (STA) method for characterizing five different salt hydrate thermochemical materials (TCM). The effects of particle size, temperature and vapor pressure are analyzed to obtain the energy storage density and thermal power density across a full hydration-dehydration cycle under controlled conditions. 

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2. Redox‐Active Oxide/molten Salt Composites for Hybrid Thermal‐Chemical Energy Storage

   https://doi.org/10.1002/aesr.202500196  

   Cai, Runxia; Bektas, Hilal; Raza, Saqlain; Massey, Jackson; Tian, Yuan; Liu, Jun; Li, Fanxing (September 2025, Advanced Energy and Sustainability Research)

   Structurally stabilized composites are promising for using phase change materials in high‐temperature thermal energy storage (TES). However, conventional skeleton materials, which typically comprise 30–50 wt% of the composite, mainly provide sensible heat storage and contribute minimally to overall energy density. This study introduces a new class of redox‐active oxide‐molten salt (ROMS) composites that overcome this limitation by combining sensible, latent, and thermochemical heat storage in a single particle. Specifically, porous, redox‐active Ca₂AlMnO_5+δ(CAM) complex oxide particles were demonstrated as a suitable support matrix, with the pores filled by eutectic NaCl/CaCl₂salt. X‐ray diffraction confirms excellent phase compatibility between CAM and the salt. Scanning electron microscopy/energy dispersive X‐ray spectroscopy and nano X‐ray tomography show good salt infiltration and wettability within the CAM pores. Thermogravimetric analysis reveals that a 60 wt% CAM/40 wt% salt composite achieves an energy density of 267 kJ kg⁻¹over a narrow 150 °C window, with ≈50 kJ kg⁻¹from thermochemical storage. Additionally, the composite shows higher thermal conductivity than salt alone, enabling faster energy storage and release. ROMS composites thus represent a novel and efficient solution for high‐performance TES. 

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3. Modelling the effects of atmospheric alkylamines on the properties of sea salt aerosols using the extended aerosols and inorganics model (E-AIM)

   Chen, K.; Zhang, K.; Qiu, C. (August 2021, The 262nd American Chemical Society National Meeting & Exposition)

   Sea salt aerosols contribute significantly to the mass loading of ambient aerosol, which may serve as cloud condensation nuclei and can contribute to light scattering in the atmosphere. Two major chemical components commonly found in sea salts are ammonium sulfate (AS) and sodium chloride (NaCl). It has been shown that alkylamines, derivatives of ammonia, can react with ammonium salts in the particle-phase to displace ammonia and likely change the particle properties. This study investigated the effects of atmospheric alkylamines on the composition and properties of sea salt aerosols using a chemical system of methylamine (MA, as a proxy of alkylamines), AS and NaCl (as a proxy of sea salt aerosol). The concentrations of ammonia and MA in aqueous/gas phases at the thermodynamic equilibrium were determined using the Extended Aerosols and Inorganics Model (E-AIM) under varying initial inputs, along with the deliquescence relative humidity (DRH) and the corresponding particle water content. Our findings indicated a notable negative relationship between MA concentration and the DRH for both AS and NaCl while the effect of MA on NaCl is smaller than that on AS. The salt of MA in the particle phase may absorb water vapor and may lead to the displacement reaction between AS and NaCl due to the low solubility of sodium sulfate. The acidity in the particle phase also played a significant role in affecting the DRH of sea salt aerosols. Since both sea salt aerosol and alkylamines are emitted into the atmosphere from the ocean in large quantities, our study suggested the potential impact of alkylamines on the environment and the climate via the modification of sea salt aerosol properties. 

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4. Tunnel structured manganese oxide nanowires as redox active electrodes for hybrid capacitive deionization

   https://doi.org/https://doi.org/10.1016/j.nanoen.2017.12.015  

   Byles, Bryan W.; Cullen, David A.; More, Karren L.; Pomerantseva, Ekaterina (January 2018, Nano energy)

   Hybrid capacitive deionization (HCDI), which combines a capacitive carbon electrode and a redox active electrode in a single device, has emerged as a promising method for water desalination, enabling higher ion removal capacity than devices containing two carbon electrodes. However, to date, the desalination performance of few redox active materials has been reported. For the first time, we present the electrochemical behavior of manganese oxide nanowires with four different tunnel crystal structures as faradaic electrodes in HCDI cells. Two of these phases are square tunnel structured manganese oxides, α-MnO2 and todorokite-MnO2. The other two phases have novel structures that cross-sectional scanning transmission electron microscopy analysis revealed to have ordered and disordered combinations of structural tunnels with different dimensions. The ion removal performance of the nanowires was evaluated not only in NaCl solution, which is traditionally used in laboratory experiments, but also in KCl and MgCl2 solutions, providing better understanding of the behavior of these materials for desalination of brackish water that contains multiple cation species. High ion removal capacities (as large as 27.8 mg g−1, 44.4 mg g−1, and 43.1 mg g−1 in NaCl, KCl, and MgCl2 solutions, respectively) and high ion removal rates (as large as 0.112 mg g−1 s−1, 0.165 mg g−1 s−1, and 0.164 mg g−1 s−1 in NaCl, KCl, and MgCl2 solutions, respectively) were achieved. By comparing ion removal capacity to structural tunnel size, it was found that smaller tunnels do not favor the removal of cations with larger hydrated radii, and more efficient removal of larger hydrated cations can be achieved by utilizing manganese oxides with larger structural tunnels. Extended HCDI cycling and ex situ X-ray diffraction analysis revealed the excellent stability of the manganese oxide electrodes in repeated ion removal/ion release cycles, and compositional analysis of the electrodes indicated that ion removal is achieved through both surface redox reactions and intercalation of ions into the structural tunnels. This work contributes to the understanding of the behavior of faradaic materials in electrochemical water desalination and elucidates the relationship between the electrode material crystal structure and the ion removal capacity/ion removal rate in various salt solutions. 

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5. Ionic Control of Microstructure and Lubrication in Charged, Physically Cross‐Linked Hydrogels

   https://doi.org/10.1002/adfm.202511763  

   Deptula, Alexander; Espinosa‐Marzal, Rosa M (September 2025, Advanced Functional Materials)

   Charged, physically cross‐linked hydrogels provide a versatile platform for designing responsive materials with programmable interfacial properties, with applications in drug delivery, biomedical devices, and biosensing. Here, poly(methacrylamide‐co‐methacrylic acid) hydrogels stabilized by a short‐range attractive, long‐range repulsive potential is investigated. By integrating microstructural, mechanical, and tribological characterization across multiple length and time scales, this work uncovers how salt addition alters not only swelling, but also the microstructure and dynamics, near‐surface stiffness and charge, and ultimately, its lubricity. Friction measurements reveal a velocity‐dependent response with distinct mixed, transition, and elastohydrodynamic regimes. Microscopic friction imaging reveals that adhesive interactions are promoted by salt and play a critical role. Unlike neutral hydrogels, where increased water content correlates with reduced friction, salts introduce additional dissipation mechanisms that can dominate over hydration effects, offering enhanced control of functional behavior. These findings provide new insights into the salt‐induced responsive behavior of poly(methacrylamide‐co‐methacrylic acid) hydrogels‐including lubrication mechanisms‐and challenges conventional interpretations of salt effects in polyelectrolyte systems. This knowledge will inform design principles for synthetic hydrogel interfaces and advance understanding of the functional behavior of hydrogel‐like materials such as biological tissues, whose lubricity‐in salinity conditions similar to those studied here‐is essential to their function. 

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