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1. StableTi ₃ C ₂ T _x MXene Ink Formulation and High‐Resolution Aerosol Jet Printing for High‐Performance MXene Supercapacitors

   https://doi.org/10.1002/smtd.202500499  

   Kouchi, Fereshteh_Rajabi; Varghese, Tony_Valayil; Burgoyne, Hailey; Mansoor, Naqsh_E; Seol, Myeong‐Lok; McKibben, Nicholas; Nirantar, Shruti; Chinnathambi, Karthik; Eixenberger, Josh; Maryon, Olivia; et al (May 2025, Small Methods)

   Abstract Lightweight energy storage devices are essential for developing compact wearable and distributed electronics, and additive manufacturing offers a scalable, low‐cost approach to fabricating such devices with complex geometries. However, additive manufacturing of high‐performance, on‐demand energy storage devices remains challenging due to the need for stable, multifunctional nanomaterial inks. Herein, the development of 2‐dimensional (2D) titanium carbide (Ti₃C₂T_xMXene) ink that is compatible with aerosol jet printing for energy storage applications is demonstrated. The developed MXene ink demonstrates long‐term chemical and physical stability, ensuring consistent printability and achieving high‐resolution prints (≈45 µm width lines) with minimal overspray. The high‐resolution aerosol‐jet printed MXene supercapacitor achieves an areal capacitance of 122 mF cm⁻²and a volumetric capacitance of 611 F cm⁻³, placing them among the highest‐performing printed supercapacitors reported to date. These findings highlight the potential of aerosol jet printing with MXene inks for on‐demand, scalable, and cost‐effective fabrication of printed electronic and electrochemical devices. 

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2. A Strongly Reducing sp ² Carbon‐Conjugated Covalent Organic Framework Formed by N ‐Heterocyclic Carbene Dimerization

   https://doi.org/10.1002/anie.202416480  

   Pitt, Tristan_A; Azbell, Tyler_J; Kim, Jaehwan; Shi, Zixiao; Muller, David_A; Addicoat, Matthew_A; Milner, Phillip_J (October 2024, Angewandte Chemie International Edition)

   Abstract Covalent organic frameworks linked by carbon‐carbon double bonds (C=C COFs) are an emerging class of crystalline, porous, and conjugated polymeric materials with potential applications in organic electronics, photocatalysis, and energy storage. Despite the rapidly growing interest in sp²carbon‐conjugated COFs, only a small number of closely related condensation reactions have been successfully employed for their synthesis to date. Herein, we report the first example of a C=C COF, CORN‐COF‐1 (CORN=Cornell University), prepared byN‐heterocyclic carbene (NHC) dimerization. In‐depth characterization reveals that CORN‐COF‐1 possesses a two‐dimensional layered structure and hexagonal guest‐accessible pores decorated with a high density of strongly reducing tetraazafulvalene linkages. Exposure of CORN‐COF‐1 to tetracyanoethylene (TCNE,E_1/2=0.13 V and −0.87 V vs. SCE) oxidizes the COF and encapsulates the radical anion TCNE⋅⁻and the dianion TCNE²⁻as guest molecules, as confirmed by spectroscopic and magnetic analysis. Notably, the reactive TCNE⋅⁻radical anion, which generally dimerizes in the solid state, is uniquely stabilized within the pores of CORN‐COF‐1. Overall, our findings broaden the toolbox of reactions available for the synthesis of redox‐active C=C COFs, paving the way for the design of novel materials. 

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3. Electrochemical lithiation of the layered superionic conductors AgCrSe₂ and CuCrSe₂

   https://doi.org/10.26434/chemrxiv-2025-wg75n  

   Moon, Seongbak; Rahman, Md Towhidur; Holzapfel, Noah P; Zevalkink, Alexandra; Augustyn, Veronica (October 2025, ChemRxiv)

   The layered transition metal chalcogenides MCrX₂ (M = Ag, Cu; X = S, Se, Te) are of interest for energy storage because chemically Li-substituted analogs were reported as superionic Li⁺ conductors. The coexistence of fast ion transport and reducible transition metal and chalcogen elements suggests that this family may offer multifunctional capability for electrochemical storage. Here, we investigate the electrochemical reduction of AgCrSe₂ and CuCrSe₂ in non-aqueous Li- and Na-ion electrolytes using electrochemical measurements coupled with ex situ characterization (scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy). Both compounds delivered high initial specific capacities (~ 560 mAh/g), corresponding to 6.64 and 5.73 Li⁺/e^- per formula unit for AgCrSe₂ and CuCrSe₂, respectively. We attribute this difference to distinct reduction pathways: 1) Li⁺ intercalation to form LiCrSe₂ and extruded Ag or Cu, 2) conversion of LiCrSe₂ to Li₂Se, and 3) formation of an Ag-Li alloy at the lowest potential, operative only in AgCrSe₂. Consistent with this proposed mechanism, step 3 was absent during reduction of AgCrSe₂ in a Na-ion electrolyte since Ag does not alloy with Na. These results demonstrate the complex reduction chemistry of MCrX₂ in the presence of alkali ions, providing insights into the use of MCrX₂ materials as alkali ion superionic conductors or high capacity electrodes for lithium or sodium-ion type batteries. 

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4. Renewable energy storage via efficient reversible hydrogenation of piperidine captured CO ₂

   https://doi.org/10.1039/C8GC00954F  

   Lu, Mi; Zhang, Jianghao; Yao, Yao; Sun, Junming; Wang, Yong; Lin, Hongfei (January 2018, Green Chemistry)

   The storage of renewable energy is the major hurdle during the transition of fossil resources to renewables. A possible solution is to convert renewable electricity to chemical energy carriers such as hydrogen for storage. Herein, a highly efficient formate-piperidine-adduct (FPA) based hydrogen storage system was developed. This system has shown rapid reaction kinetics of both hydrogenation of piperidine-captured CO 2 and dehydrogenation of the FPA over a carbon-supported palladium nano-catalyst under mild operating conditions. Moreover, the FPA solution based hydrogen storage system is advantageous owing to the generation of high-purity hydrogen, which is free of carbon monoxide and ammonia. In situ ATR-FTIR characterization was performed in order to provide insight into the reaction mechanisms involved. By integrating this breakthrough hydrogen storage system with renewable hydrogen and polymer electrolyte membrane fuel cells (PEMFC), in-demand cost-effective rechargeable hydrogen batteries could be realized for renewable energy storage. 

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5. Structure Effect on Pseudocapacitive Properties of A ₂ LaMn ₂ O ₇ (A = Ca, Sr)

   https://doi.org/10.1002/ente.202201249  

   Kananke-Gamage, Chandana C. W.; Ramezanipour, Farshid (January 2023, Energy Technology)

   Herein, the effect of structure on pseudocapacitive properties in alkaline conditions is demonstrated through the investigation of isoelectronic oxides Ca₂LaMn₂O₇and Sr₂LaMn₂O₇, where the difference in ionic radii of Ca²⁺and Sr²⁺leads to a change in structure and lattice symmetry, resulting in an orthorhombicCmcmstructure for the former and a tetragonalI4/mmmstructure for the latter. While calcium and strontium do not make a direct contribution to the near‐surface faradaic processes that are essential to the pseudocapacitive properties, their effect on the structure leads to a change in the oxygen intercalation process and the associated pseudocapacitive energy storage. It is shown that Sr₂LaMn₂O₇has a significantly greater specific capacitance than Ca₂LaMn₂O₇. In addition, the former shows a considerably higher‐energy density compared to the latter. Furthermore, these materials show highly stable energy‐storage properties, and retain their specific capacitance over 10 000 cycles of charge–discharge in a symmetric pseudocapacitive cell. Importantly, these findings show the structure–property relationships, where a change in the structure and lattice symmetry can result in a significant change in pseudocapacitive charge–discharge properties in isoelectronic systems. 

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