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Carbazole polymers attract significant attention as promising luminophores, organic electronic and photovoltaic materials, photo/electrocatalysts, energy storage materials, redox mediators and catalysts. However, the oxidation potential of the commercially available poly(vinylcarbazole) is insufficient for some applications such as high-voltage Li-Ion batteries. We have proposed a monomer for the novel polycarbazole with an increased oxidation potential, which will be compatible with high-voltage cathode materials for Li-Ion. In addition, the proposed polymer is an interesting substrate for the further carbonization to obtain N-doped carbons with a high electrocatalytic activity level. [ABSTRACT FROM AUTHOR]

Various iron oxides have been proven to be promising anode materials for metal-ion batteries due to their natural abundance, high theoretical capacity, ease of preparation, and environmental friendliness. However, the synthesis of iron oxide-based composites requires complex approaches, especially when it comes to composites with intrinsically conductive polymers. In this work, we propose a one-step microplasma synthesis of polyaniline-coated urchin-like FeOOH nanoparticles (FeOOH/PANI) for applications as anodes in lithium-ion batteries. The material shows excellent electrochemical properties, providing an initial capacity of ca. 1600 mA∙h∙g−1 at 0.05 A∙g−1 and 900 mA∙g−1 at 1.2 A∙g−1. Further cycling led to a capacity decrease to 150 mA∙h∙g−1 by the 60th cycle, followed by a recovery that maintained the capacity at 767 mA∙h∙g−1 after 2000 cycles at 1.2 A∙g−1 and restored the full initial capacity of 1600 mA∙h∙g−1 at a low current density of 0.05 A∙g−1. Electrochemical milling—the phenomenon we confirmed via a combination of physico-chemical and electrochemical techniques—caused the material to exhibit interesting behavior. The anodes also exhibited high performance in a full cell with NMC532, which provided an energy density of 224 Wh∙kg−1, comparable to the reference cell with a graphite anode (264 Wh∙kg−1). [ABSTRACT FROM AUTHOR]

The performance of lithium-ion batteries (LIBs) relies on the characteristics of the cathode material, including both intentionally applied coatings and naturally formed surface layers or binder adhesion. This study investigated the influence of the ion-permeable surface fraction, distribution, and characteristics of the coating on the performance of a lithium iron phosphate (LFP) electrode material. We developed an extended Newman-type half-cell model and examined the impact of coating parameters on the galvanostatic discharge curves of the LFP electrode material. The study found that the ion-permeable surface fraction has a significant influence on the diffusion and charge transfer characteristics of the electrode material. A decrease in the ion-permeable surface fraction leads to a decrease in the measured diffusion coefficients and to an increase in the overall coating resistance of the electrode material. Interestingly, the distribution of the ion-permeable surface also plays a role in the diffusion characteristics, with a coarsely dispersed coating resulting in lower diffusion coefficients. Additionally, the coating characteristics significantly affect the polarization and capacity of the electrode material at different C-rates. The model was used to approximate the experimental discharge curves of the LFP-based composite electrodes with two different compositions, and the simulated data showed satisfactory agreement with the experiment. Thus, we believe that the developed model and its further extension will be useful in numerical simulations that aim to facilitate the search for optimal compositions. [ABSTRACT FROM AUTHOR]

Safety issues with lithium-ion batteries prevent their widespread use in critical areas of technology. Various types of protective systems have been proposed to prevent thermal runaway and subsequent battery combustion. Among them, thermoresistive systems, representing polymer composites that sharply increase their resistance when the temperature rises, have been actively investigated. However, they are triggered only when the heating of the battery has already occurred, i.e., the system undergoes irreversible changes. This paper describes a new type of protective polymer layer based on the intrinsically conducting polymer poly[Ni(CH3OSalen)]. The response mechanism of this layer is based on an increase in resistance both when heated and when the cell voltage exceeds the permissible range. This makes it possible to stop undesirable processes at an earlier stage. The properties of the polymer itself and of the lithium-ion batteries modified by the protective layer have been studied. It is shown that the introduction of the polymer protective layer into the battery design leads to a rapid increase of the internal resistance at short circuit, which reduces the discharge current and sharply reduces the heat release. The effectiveness of the protection is confirmed by analysis of the battery components before the short circuit and after it. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries production increase ultimately leads to toxic waste. Today, recycling of the spent lithium-ion batteries becomes extremely important with much attention paid to recycling of cathode materials. Graphite recovery receives less attention due to low economic benefits, high costs of material cleaning and low cycling stability. In fact, regenerating graphite with low-cost technology is of great importance to solve the problem of recycling spent graphite and environmental contamination. This paper presents a variant of graphite recycling using low-cost plasma solution treatment (less than 28 kWh·kg graphite −1), leading to a capacitive and powerful material. The results were confirmed by cycling of cells based on recycled graphite for 500 cycles at 0.3 A·g−1 with excellent stability and high capacity (392 mAh·g−1), which is greater than the graphite theoretical capacity due to the formation of graphene oxide from the surface graphite layers. The treatment duration does not affect the interplanar distance of the obtained graphites. Long cycling shows a change in the shape of the charge curves with a graphene fraction increase. For all samples the kinetic characteristics were also evaluated: the dependence of the diffusion coefficient, SEI resistance and charge transfer resistance on the potential and the intercalation rate constant. [Display omitted] • Low-consumption plasma solution graphite recycling (< 28 kWh·kg graphite −1). • The excellent stability – 500 cycles, 392 mAh·g−1, 0.3 A·g−1. • High diffusion coefficient of about 10–9 - 10–10 cm2·s−1. • Kinetic parameters (D , R ct , R SEI) dependence on plasma solution treatment time. [ABSTRACT FROM AUTHOR]

Materials with a positive temperature coefficient have many applications, including overcharge and over-temperature protection in lithium-ion (Li-ion) batteries. The thermoresistive properties of an electrically conductive polymer, based on a Ni(salen)-type backbone, known as polyNiMeOSalen, were evaluated by means of in situ resistivity measurements. It was found that the polymer was conductive at temperatures below 220 °C; however, the polymer increased in resistivity by three orders of magnitude upon reaching 250 °C. Thermogravimetric results combined with elemental analyses revealed that the switch from the insulation stage to the conductive stage resulted from thermally dedoping the polymer. Electrochemical studies demonstrated that a polymer retains its electroactivity when it is heated and can be recovered to a conductive state through oxidation via electrochemical doping in an electrolyte solution. [ABSTRACT FROM AUTHOR]

Conjugated coordination polymers attract attention as materials for electrochemical energy storage, mostly as cathode materials for supercapacitors. Faradaic capacity may be introduced to such materials using redox-active building blocks, metals, or ligands. Using this strategy, a novel hybrid cathode material was developed based on a Ni2+ metal-organic polymer. The proposed material, in addition to double-layer capacitance, shows high pseudocapacitance, which arises from the contributions of both the metal center and ligand. A tailoring strategy in the ligand design allows us to minimize the molecular weight of the ligand, which increases its gravimetric energy. According to computational results, the ligand makes the prevailing contribution to the pseudocapacitance of the material. Different approaches to metal–organic polymer (MOP) synthesis were implemented, and the obtained materials were examined by FTIR, Raman spectroscopy, powder XRD, SEM/EDX (energy-dispersive X-ray spectroscopy), TEM, and thermal analysis. Energy-storage performance was comparatively studied with cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD). As a result, materials with an excellent discharge capacity were obtained, reaching the gravimetric energy density of common inorganic cathode materials. [ABSTRACT FROM AUTHOR]

Electrochemical cells using LiFePO4 cathode material are considered one of the safest and most resistant to overcharging among Li-ion batteries. However, if LiFePO4-based electrodes are exposed to high potentials, surface and structural changes may occur in the electrode material. In this study Li/LiFePO4 half-cells were overcharged under different modes with variable cut-off voltages and charge currents. The change in voltage profile, discharge capacity, surface layers composition, and crystalline structure were characterized after overcharge cycles. It was demonstrated that the cathode material is resistant to short-term overcharging up to 5 V, but undergoes irreversible changes with increasing overcharge time or potential. Thus, despite the well-known tolerance of LiFePO4-based batteries to overcharge, a long overcharge time or high cut-off voltage leads to destructive changes in the cathode and should be avoided. [ABSTRACT FROM AUTHOR]

The Cover Feature illustrates light‐driven oxygen reduction to hydrogen peroxide catalyzed by polymerized Ni–salen complexes. More information can be found in the Communication by A. S. Konev et al on page 3138 in Issue 21, 2018 (DOI: 10.1002/celc.201800846). [ABSTRACT FROM AUTHOR]

[Display omitted] • A high-performance amorphous FeOOH-based anode is developed for Li-ion batteries. • One-step atmospheric plasma-assisted synthesis of FeOOH composite with graphite. • A capacity of ∼ 750 mAh g−1 is sustained after 500 cycles at 0.3 A g−1. • A capacity of ∼ 550 mAh g−1 is sustained after 2000 cycles at 1.2 A g−1. Iron oxide derivatives are promising materials for large-scale use as anode materials, owing to their natural abundance, inexpensiveness, and high theoretical capacity. Here, we synthesized amorphous urchin-like FeOOH nanoparticles and their graphite composite (FeOOH/Gr) in a one-step atmospheric plasma-assisted procedure and employed it in anode materials for Li-ion batteries. The obtained FeOOH nanoparticles are up to 300 nm in diameter with a needle thickness of about (3–10) nm, while FeOOH/Gr composite consists of graphite sheets covered with FeOOH needles. The FeOOH and FeOOH/Gr materials show excellent electrochemical performance as anode materials, with 633 mAh g−1 and 740 mAh g−1 at 0.3 A g−1 after 500 cycles, 353 mAh g−1 and 542 mAh g−1 at 1.2 A g−1 after 2000 cycles, respectively. By analyzing the state of the material at various stages of their life, we identify electrochemical milling as the performance-boosting process responsible for the 277% specific capacity increase during charge-discharge cycling after 50 cycles. [ABSTRACT FROM AUTHOR]