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Polymer-based electrolytes have attracted ever-increasing attention for solid-state batteries due to their excellent flexibility and processability. Among them, poly(vinylidene difluoride) (PVDF)-based electrolytes with high ionic conductivity, wide electrochemical stability window, and good mechanical properties show great potential and have been widely investigated by using different Li salts, solvents, and inorganic fillers. Here, we report the influence of the molecular weight of PVDF itself on the electrochemical properties of the electrolytes by using two kinds of common PVDF polymers, i.e., PVDF 761 and 5130. Our results demonstrate that the electrolyte with a larger molecular weight (PVDF 5130) has a denser structure and lower crystallinity, and thus much better electrochemical performance, than one with a smaller molecular weight (PVDF 761). With PVDF 5130, the LiFePO

2-Acrylamido-2-methylpropane sulfonic acid (AMPS) is used as an organic additive for poly(vinylidene fluoride) (PVDF)-based polymer electrolytes to assist with the fast Li-ion conduction and formation of a stable interface.

Rechargeable lithium-oxygen (Li-O2) batteries are the next generation energy storage devices due to their ultrahigh theoretical capacity. Redox mediators (RMs) are widely used as a homogenous electrocatalyst in non-aqueous Li-O2 batteries to enhance their discharge capacity and reduce charge overpotential. However, the shuttle effect of RMs in the electrolyte solution usually leads to corrosion of the Li metal anode and uneven Li deposition on the anode surface, resulting in unwanted consumption of electrocatalysts and deterioration of the cells. It is therefore necessary to take some measures to prevent the shuttle effect of RMs and fully utilize the soluble electrocatalysts. Herein, we summarize the strategies to suppress the RM shuttle effect reported in recent years, including electrolyte additives, protective separators and electrode modification. The mechanisms of these strategies are analyzed and their corresponding requirements are discussed. The electrochemical properties of Li-O2 batteries with different strategies are summarized and compared. The challenges and perspectives on preventing the shuttle effect of RMs are described for future study. This review provides guidance for achieving shuttle-free redox mediation and for designing Li-O2 cells with a long cycle life, high energy efficiency and highly reversible electrochemical reactions.

To improve the performance of lithium-oxygen (Li-O2) batteries with an extremely high theoretical energy density, redox mediators (RMs) are usually added to liquid electrolytes to assist with the charge process and reduce the overpotential. However, the shuttle effect and the instability of RMs towards a Li metal anode degrade the cycle performance of Li-O2 batteries. Herein, we report a volatilization-dissolution strategy to supply RMs by introducing 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) into the O2 atmosphere (TEMPO-O2) outside an assembled cell. Due to not directly adding RMs to liquid electrolytes, the parasitic reactions between the Li metal anode and TEMPO, including the TEMPO's shuttle effect, are alleviated. TEMPO-O2 mediates the formation-decomposition of lithium peroxide (Li2O2) in Li-O2 batteries and shows a uniform catalytic effect towards commercial Li2O2. Thanks to the continuous redox mediation of volatile TEMPO and the suppression of the RM's shuttle effect, the Li-O2 battery demonstrates an ultra-long cycle life of 400 cycles (1600 h) at 250 mA g−1. Our strategy to supply volatile RMs shows a universal adaptability towards different kinds of cathodes and electrolytes, which may trigger broad applications in various gas-involved Li metal batteries.

In this paper, satellite data from five isolated power plants were used to explore the change local emissions levels belonged to the vicinity of the power plant before and after ultra-low emissions (ULE) retrofitted. Sulphur dioxide (SO2) and nitrogen dioxide (NO2) observations from Ozone monitoring Instrument (OMI) satellite data were used to evaluate the emission changes of the power plants retrofitted by ULE technology. Meanwhile, the actual emission reduction effect of isolated power plants was evaluated by the OMI data. It was observed that the isolated power plants have shown obvious point source characteristics. The average annual SO2 emission reduction ratio of SZ, ZD, JJ, ND and BD power plants after ultra-low transformation is 43.7%, 56.9%, 29.0%, 34.6% and 26.8%, respectively, compared with that before the transformation, while the corresponding PBL-SO2 column concentration reduction ratio is 27.0%, 14.3%, 15.6%, 26.6% and 4.2%, respectively. The average annual NOx emission reduction ratio of the power plants after ultra-low transformation is 44.7%,79.3%,29.0%,73.2% and 29.8%, respectively, compared with that before the transformation, while the corresponding NO2 column concentration reduction ratio is 7.0%,27.2%,25.7%,8.9% and 5.6%, respectively. The trend of emission reduction before and after the ULE retrofitted of SO2 and NO2 column concentration by satellite observation is consistent with the calculated trend of emission reduction. Satellite observations have confirmed the emission reduction effect of ULE technology.

Nationwide severe air pollution has prompted China to mandate the adoption of ultralow emissions (ULE) control technologies at all of its coal-fired power plants by 2020. This process has accelerated greatly since 2014 and, combined with operational adjustments related to overcapacity, has reduced the emissions of nitrogen oxides (NOx), sulfur dioxide (SO2), and particulate matter (PM). Yet the quantitative understanding of ULE benefits is poor. Using detailed emissions data from 38 units at 17 power plants, corresponding to 10 combinations of ULE technologies representative of the Chinese power sector, we show that emissions factors for NOx, SO2, and PM are up to 1–2 orders of magnitude lower after ULE retrofitting. The effectiveness in cutting emissions shows a large spread across the various ULE technology combinations, providing an opportunity to choose the most efficient, economically viable technology (or a combination of technologies) in the future. The temporal variations in emissions at hourly re...

Solid polymer electrolytes with large ionic conductivity, high ionic transference number, and good interfacial compatibility with electrodes are highly desired for solid-state batteries. However, unwanted polarizations and side reactions occurring in traditional dual-ion polymer conductors hinder their practical applications. Here, single-ion polymer conductors (SIPCs) with exceptional selectivity for Li-ion conduction (Li-ion transference number up to 0.93), high room-temperature ionic conductivity of about 10

An intra-fibre wavelength conversion (IFWC) adopting ROADM-like structure for upgrading MG-OXC router is proposed. A minimum resource first assignment (MRFA) algorithm aimed at this specific structure is also developed for better performance.