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Ni-Ion-Chelating Strategy for Mitigating the Deterioration of Li-Ion Batteries with Nickel-Rich Cathodes
No full textNi-rich cathodes are the most promising candidates for realizing high-energy-density Li-ion batteries. However, the high-valence Ni4+ ions formed in highly delithiated states are prone to reduction to lower valence states, such as Ni3+ and Ni2+, which may cause lattice oxygen loss, cation mixing, and Ni ion dissolution. Further, LiPF6, a key salt in commercialized electrolytes, undergoes hydrolysis to produce acidic compounds, which accelerate Ni-ion dissolution and the interfacial deterioration of the Ni-rich cathode. Dissolved Ni ions migrate and deposit on the surface of the graphite anode, causing continuous electrolyte decomposition and threatening battery safety by forming Li dendrites on the anode. Herein, 1,2-bis(diphenylphosphino)ethane (DPPE) chelates Ni ions dissolved from the Ni-rich cathode using bidentate phosphine moieties and alleviates LiPF6 hydrolysis via complexation with PF5. Further, DPPE reduces the generation of corrosive HF and HPO2F2 substantially compared to the amounts observed using trimethyl phosphite and tris(trimethylsilyl) phosphite, which are HF-scavenging additives. Li-ion cells with Ni-rich cathodes and graphite anodes containing DPPE exhibit remarkable discharge capacity retentions of 83.4%, with high Coulombic efficiencies of >99.99% after 300 cycles at 45 degrees C. The results of this study will promote the development of electrolyte additives
High-level periodic conjugated terpolymers through AA/BB monomer pair-type terpolymerization improve performance of polymer solar cells
No full textWith a growing interest in developing high-performance ??-conjugated terpolymers via random terpolymerization, new synthetic approaches resulting in higher-quality terpolymers with improved backbone regularity are needed to help make organic optoelectronic and photovoltaic applications more prosperous. Herein, we report an AA/BB monomer pair-type terpolymerization protocol that renders semi-sequence-controlled (SSC) terpolymers by polymerizing the aperiodically repeating units into the preferentially formed periodic, alternating polymeric block sequences, unlike the conventional random terpolymerization for producing terpolymers with irregular repeating sequences. A close comparison of SSC- and conventional terpolymerization-derived terpolymers indicate detectable differences in the absorption, energetic properties, carrier transport, energy loss, and morphological characteristics. The optimal SSC terpolymer-based polymer solar cells (PSCs) outperform the conventional terpolymerization-derived counterparts in power conversion efficiency (PCE). Moreover, the optimal SSC terpolymer-based PSCs processed by an eco-friendly solvent/additive system also exhibit outstanding PCEs of 16.52 % (small area of 0.041 cm2) and 15.50 % (large area of 1 cm2). To the best our knowledge, it is the highest value among tetrahydrofuran-processed PSCs. This SSC terpolymerization shows considerable promise in synthesizing high-quality in-chain terpolymers with high backbone sequence control without sacrificing their inherent beneficial features, providing high potential for further improving their PSC performances
Energy-Efficient Power Management Interface with Adaptive HV Multimode Stimulation for Power-Sensor Integrated Patch-Type Systems
No full textAn energy-efficient power management interface (PMI) with adaptive high-voltage (HV) stimulation capability is presented for patch-type healthcare devices where power management and sensor readout circuits are integrated. For efficient power supply, it proposes a multimode buck converter with an adaptive mode controller, delivering 95.6% peak power conversion efficiency and over 90% efficiency across a wide 4???440 mA output current range. For energy-efficient stimulation, a HV stimulation system is designed to perform mode-adaptive on/off control, where the charge pump (CP) is adopted for periodic power saving. The CP output is adaptively tuned to minimize the stimulator's power waste by utilizing a bio-impedance path in the sensor circuit. The stimulation core supports multimode functionality of current-/voltage-controlled stimulations with monopolar and bipolar modes, providing ten kinds of various stimulation waveform shape. For efficient system operation, battery interface circuits are included to monitor state-of-charge (SOC) conditions, and a device power adjustment scheme is proposed to provide SOC-based maximum 28% power reduced optimal operation of high-resolution and low-power. The power-sensor integrated circuits were fabricated in a 0.18-??m CMOS process, and the proposed schemes were experimentally verified. For system-level feasibility, a patch-type device prototype was manufactured, and both power and bio-signal interfaces were functionally demonstrated
Dual-responsive photonic multilayers in combination with a smartphone application as high-security anti-counterfeiting devices
No full textA new concept for dual-responsive one-dimensional (1D) photonic crystal (PC) multilayers is proposed herein. The novel PC-based systems rely on the humidity from the human breath and fluorescence triggered by Al3+ coordination to act as high-security anti-counterfeiting labels to be used in combination with a smartphone application. The dual-responsive patterned film is fabricated via the alternating deposition of photo-crosslinkable poly(2-vinylnaphthalene-co-benzophenone acrylate) and 51%-quaternized poly(4-vinylpyridine-co-benzophenone acrylate) onto a transparent polyethylene terephthalate substrate to obtain 1D PC multilayers, followed by the introduction of a poly([(2-hydroxybenzylidene)-4-vinylbenzohydrazide-co-benzophenonyl acrylate) top coating. The obtained system is then exposed to ultraviolet light irradiation through variously patterned masks. The patterned films exhibit vivid dual color transitions in high-humidity environments along with remarkable turn-on fluorescence, following the coordination of Al3+ ions upon spraying with a 1 wt% Al(NO3)3 solution. Notably, the efficacy of the combination between the two-step security function of the flexible patterned multilayer films and a smartphone app was also demonstrated. The first level of security involves the determination of the RGB color value before and after a color change triggered by blowing onto the film. The second level of security involves the revelation of hidden fluorescent shapes under ultraviolet light irradiation after Al (NO3)3 spraying
Application and development of a machine learning based model for identification of apartment building types - Analysis of apartment site characteristics based on main building shape -
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Enhancing ammonia production rates from electrochemical nitrogen reduction by engineering three-phase boundary with phosphorus-activated Cu catalysts
No full textElectrochemical N2 reduction reaction (eNRR) over Cu-based catalysts suffers from an intrinsically low activity of Cu for activation of stable N2 molecules and the limited supply of N2 to the catalyst due to its low solubility in aqueous electrolytes. Herein, we propose phosphorus-activated Cu electrocatalysts to generate electron-deficient Cu sites on the catalyst surface to promote the adsorption of N2 molecules. The eNRR system is further modified using a gas diffusion electrode (GDE) coated with polytetrafluo-roethylene (PTFE) to form an effective three-phase boundary of liquid water -gas N2 -solid catalyst to facilitate easy access of N2 to the catalytic sites. As a result, the new catalyst in the flow-type cell records a Faradaic efficiency of 13.15% and an NH3 production rate of 7.69 lg h-1 cm-2 at-0.2 VRHE, which rep-resent 3.56 and 59.2 times increases from those obtained with a pristine Cu electrode in a typical elec-trolytic cell. This work represents a successful demonstration of dual modification strategies; catalyst modification and N2 supplying system engineering, and the results would provide a useful platform for further developments of electrocatalysts and reaction systems. & COPY; 2023 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved