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Li-metal batteries (LMBs) are regarded as next generation storage devices for applications in a wide range of fields, such as electric vehicles and grid-scale energy storage. Unfortunately, their practical applications have been restricted by some defects including safety hazards, low coulombic efficiency (CE), and lithium dendrite growth. Inspired by the low-cost electrolytes in industrial applications, a low concentration bisalt electrolyte (LBE) for practical LMBs is proposed in this work. The synergistic effect of bisalt (0.3 M lithium bis(fluorosulfonyl)imide (LiFSI) and 0.2 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)) and weakly solvating solvent (1,4-dioxane (DX)), provides robust and conductive solid/cathode electrolyte interphase (SEI/CEI) layers on the Li metal anode and LiFePO4 (LFP) cathode, respectively. The majority of salt anions exist in associated states, such as contact ion pairs (CIPs) and aggregates (AGGs), as observed in highly concentrated electrolytes. These ion associates are involved in the formation of stable and LiF-rich SEI and CEI layers which suppress the dendrite growth on the Li anode and prevent parasitic reactions on the LFP cathode. The average CE of the Li‖Cu cells in the LBE was 99.2%. Furthermore, LBE also improved the cycling stability of a Li‖LiFP cell, with a capacity retention of 78.5% after 400 cycles. These results demonstrate the benefits of LBE, paving way for the industrial application of LCE. [ABSTRACT FROM AUTHOR]

Supercapacitors exhibit excellent power density and durability due to their high ionic conductivity and the electrochemical stability of nitrile or carbonate-based electrolytes. However, these commonly used electrolytes have inherent risks due to the high flammability of organic solvents. With the widespread use of supercapacitors, such safety problems have aroused great concerns. Although considerable research efforts have been devoted to improve the safety of lithium-ion batteries, research focusing on safe supercapacitor performance is limited. Here a nonflammable organic electrolyte based on trimethyl phosphate (TMP) solvent is proposed for safe operation. The physical and electrochemical characteristics of the TMP-based electrolyte are investigated by self-extinguishing time, ionic conductivity, viscosity, cyclic voltammetry, and charge–discharge measurements. We demonstrate that the TMP-based electrolyte enables dramatic improvements in safety as well as good transport properties and stable charge–discharge cycling for 10 000 cycles at a high working voltage (3.3 V) at both low and high current densities. The TMP electrolyte was found to decompose and form a film on the electrode surface preventing further electrolyte decomposition. This helps to widen the electrochemical stability window of supercapacitors, realizing high energy and power by increasing the upper voltage. Therefore, the electrolyte system reported here is a promising candidate for safe and performant supercapacitors in large-scale energy storage applications. [ABSTRACT FROM AUTHOR]

Maleic anhydride derivatives were evaluated as catalysts in N -oxidation of various pyridine substrates using hydrogen peroxide (H 2 O 2 ). Depending on the electronic properties of the pyridine substrates, pyridines with electron-donating groups reacted well with 2,3-dimethylmaleic anhydride (DMMA). In contrast, 1-cyclohexene-1, 2-dicarboxylic anhydride (CHMA) was most effective for electron-deficient pyridines. The different performance of these two anhydrides is attributed to the diacid-anhydride equilibrium, which is crucial for regenerating the peracid oxidant through an anhydride intermediate in the catalytic cycle. This approach using a catalytic amount of anhydride with H 2 O 2 has the potential to replace stoichiometric amounts of percarboxylic acid as an oxidant for a broader range of organic substrates., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

To achieve a zero-carbon-emission society, it is essential to increase the use of clean and renewable energy. Yet, renewable energy resources present constraints in terms of geographical locations and limited time intervals for energy generation. Therefore, there is a surging demand for developing high-performance energy storage systems (ESSs) to effectively store the energy during the peak time and use the energy during the trough period. To this end, supercapacitors hold great promise as short-term ESSs for rapid power recovery or frequency regulation to improve the quality and reliability of power supply. In particular, the electrical double layer capacitor (EDLC) which offers long and stable cycle retention, high power densities, and fast charge/discharge characteristics with a moderate operating voltage window, is a suitable candidate. Yet, for implementation of the EDLC in ESSs, further research effort is required in terms of increasing the operating voltage and energy densities while maintaining the long-term cycle stability and power densities which are desirable aspects for ESS operation. Here, we examine the advances in EDLC research to achieve a high operating voltage window along with high energy densities, covering from materials and electrolytes to long-term device perspectives for next-generation supercapacitor-based ESSs., Competing Interests: The authors declare that they have no known competing financial interests for the work reported in this paper., (This journal is © The Royal Society of Chemistry.)

The catalytic efficiency and recyclability of poly(maleic anhydride- alt -1-octadecene) (Od-MA) and poly(maleic anhydride- alt -1-isobutylene) (Bu-MA) were evaluated for use in the development of a metal-free, reusable catalyst for the oxidation of pyridines to pyridine N -oxides in the presence of H 2 O 2 . The Od-MA catalyst was easily recovered via filtration with recovery yields exceeding 99.8%. The catalyst retained its activity after multiple uses and did not require any treatment for reuse. The Od-MA and H 2 O 2 catalytic system described herein is eco-friendly, operationally simple, and cost-effective; thus, it is industrially applicable. Od-MA and H 2 O 2 could potentially be used in place of percarboxylic acid as an oxidant in a wide range of oxidation reactions., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

We designed and synthesized regio-regular alternating diketopyrrolopyrrole (DPP)-based D 1 -A-D 2 -A terpolymers (PDPPF2T2DPP-T2, PDPPF2T2DPP-TVT, and PDPPF2T2DPP-DTT) using a primary donor (D 1 ) [3,3'-difluoro-2,2'-bithiophene (F2T2)] and a secondary donor (D 2 ) [2,2'-bithiophene (T2), ( E )-1,2-di(thiophen-2-yl)ethene (TVT), or dithieno[3,2- b :2',3'- d ]thiophene (DTT)]. A PDPP2DT-F2T2 D-A polymer was synthesized as well to compare optical, electronic, and photovoltaic properties. The absorption peaks of the terpolymers (PDPPF2T2DPP-T2, PDPPF2T2DPP-TVT, and PDPPF2T2DPP-DTT) were longer ( λ max = 801-810 nm) than the peak of the PDPP2DT-F2T2 polymer ( λ max = 799 nm), which is associated with the high-lying HOMO levels of the terpolymers (-5.08 to -5.13 eV) compared with the level of the PDPP2DT-F2T2 polymer (-5.38 eV). The photovoltaic properties of these DPP-based polymers were investigated under simulated AM 1.5G sunlight (100 mW cm -2 ) with a conventional structure (ITO/PEDOT:PSS/polymer:PC 71 BM/Al). The open-circuit voltages ( V oc ) of photovoltaic devices containing the terpolymers were slightly lower (0.68-0.70 V) than the V oc of the device containing the PDPP2DT-F2T2 polymer (0.79 V). The short-circuit current ( J sc ) of the PDPPF2T2DPP-DTT device was significantly improved (14.14 mA cm -2 ) compared with that of the PDPP2DT-F2T2 device (8.29 mA cm -2 ). As a result, the power conversion efficiency (PCE) of the PDPPF2T2DPP-DTT device (6.35%) was increased by 33% compared with that of the simple D-A-type PDPP2DT-F2T2 device (4.78%). The highest J sc and PCE values (the PDPPF2T2DPP-DTT device) were attributed to an optimal nanoscopically mixed morphology and strong interchain packing with a high face-on orientation in the blend film state. The study demonstrated that our strategy of using multiple donors in a regio-regular alternating fashion could fine-tune the optical, electronic, and morphological properties of D-A-type polymers, enhancing the performance of polymer solar cells., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Recent measurements using two-dimensional electronic spectroscopy (2D ES) have shown that the initial dynamic response of photosynthetic proteins can involve quantum coherence. We show how electronic coherence can be differentiated from vibrational coherence in 2D ES. On that basis we conclude that both electronic and vibrational coherences are observed in the phycobiliprotein light-harvesting complex PC645 from Chroomonas sp. CCMP270 at ambient temperature. These light-harvesting antenna proteins of the cryptophyte algae are suspended in the lumen, where the pH drops significantly under sustained illumination by sunlight. Here we measured 2D ES of PC645 at increasing levels of acidity to determine if the change in pH affects the quantum coherence; quantitative analysis reveals that the dynamics are insensitive to the pH change.