Lithium–sulfur (Li–S) batteries are regarded as the most promising next‐generation energy storage systems due to their high energy density and cost‐effectiveness. However, their practical applications are seriously hindered by several inevitable drawbacks, especially the shuttle effects of soluble lithium polysulfides (LiPSs) which lead to rapid capacity decay and short cycling lifespan. This review specifically concentrates on the shuttle path of LiPSs and their interaction with the corresponding cell components along the moving way, systematically retrospect the recent advances and strategies toward polysulfides diffusion suppression. Overall, the strategies for the shuttle effect inhibition can be classified into four parts, including capturing the LiPSs in the sulfur cathode, reducing the dissolution in electrolytes, blocking the shuttle channels by functional separators, and preventing the chemical reaction between LiPSs and Li metal anode. Herein, the fundamental aspect of Li–S batteries is introduced first to give an in‐deep understanding of the generation and shuttle effect of LiPSs. Then, the corresponding strategies toward LiPSs shuttle inhibition along the diffusion path are discussed step by step. Finally, general conclusions and perspectives for future research on shuttle issues and practical application of Li–S batteries are proposed.

Silicon nanoparticles (SiNPs) with a median size of 51 nm are prepared by the sand mill from waste silicon, and then carbon-interweaved SiNPs/graphite anode materials are designed. Because of the size of SiNPs is restricted below a critical fracture size of 150 nm as well as the rational decoration of carbon and graphite, fracture of SiNPs, and volume deformation of active materials are highly alleviated, leading to low impedance, enhanced electrochemical reaction kinetics, and good electronic connection between active materials and current collector. Furthermore, delithiation reversibility of the formed crystalline Li15Si4 alloy is enhanced. As a result, the anode with 10.5 wt % content of Si (including SiO x ) delivers a properly high initial reversible capacity of 505 mA h g–1, high cycling stability with capacity retentions of 86.3%, and 91.5% at 0.1 and 1 A g–1 after 500 cycles, respectively. After cycling at a series of higher current densities, the reversible capacity recovers to the original level completely (100% recovery) when the current density is set back to the original value, exhibiting outstanding rate performance. The results indicate that the silicon–carbon anode can achieve high cycling performances with enhanced delithiation reversibility of the formed crystalline Li15Si4 alloy by restricting size of SiNPs and decoration of carbon materials, which are discussed systematically. The SiNPs are recycled from waste Si, and synthetic strategy of anode materials is very facile, cost-effective, and nontoxic, which has potential for industrial production.

Silicon (Si) has been regarded as a promising alternative anode to the commercial graphite anode for high performance lithium ion batteries (LIBs) because of its ultrahigh theoretical capacity. However, the...

most widely and regarded as potential candidates, considering their higher theoretical gravimetric energy density (Li-S: 2615 Wh kg −1 , Na-S: 1673 Wh kg −1 ) than that of Li-ion (Lithium ion) batteries. [2] Despite possessing about twice the theoretical gravimetric and volumetric energy densities of Na-S batteries (Figure 1b), the sustainable development of Li-S batteries is still constrained by the low earth abundance (0.0017 wt%) and the resultant fastly rising price of lithium (Li) source. [3] Not only that, the main Li source, lithium carbonate, is usually prepared by the single production method, which is highly dependent on salt lake brines concentrated in South America geographically. [4] In sharp contrast, sodium (Na) sources are abundant (2.3 wt%) and scattered all over the world, as well as they can be prepared industrially in various ways, which will bring economic benefits. Therefore, although no substantial improvements in energy density and long-term durability are realized via switching to Na as the Li alternative in metal-sulfur batteries, developing Na-S batteries is more available for mitigating geostrategic and geo-economic competition and solving long-term energy bottlenecks in terms of technoeconomics. [3,5] Moreover, different from Li metal possessing high reaction activity to aluminum (Al), Na metal anode does not react with Al so that light and cheap Al foil can be used as the alternative anode current collector to Cu counterpart in the Na-S system, which could heighten gravimetric energy density and reduce cost, especially in pouch cells.Both Li and Na are alkali metals and have body-centered cubic crystal structures. These similarities in fundamental characteristics make Na metal possess similar physical and chemical properties to Li metal, such as high reaction activity, low melt temperature, vulnerability to the plastic deformation below the low yield strength, on the other hand, cause similar issues when Na or Li metal anodes are coupled with S cathode to assemble metal-sulfur batteries. [5] Subjected to the imperfection of alkali anode and S cathode, several similar challenges must be overcome for the practical application of Li-S and Na-S batteries, including uncontrollable growth of Li or Na dendrites, unstable solid electrolyte interface (SEI) layer on the surface of the anode, sluggish conversion kinetics between S active material and polysulfide intermediates, the dissolution and shuttle Metal-sulfur batteries exhibit great potential as next-generation rechargeable batteries due to the low sulfur cost and high theoretical energy density. Sodium-sulfur (Na-S) batteries present higher feasibility of long-term development than lithium-sulfur (Li-S) batteries in technoeconomic and geopolitical terms. Both lithium and sodium are alkali metal elements with body-centered cubic structures, leading to similar physical and chemical properties and exposing similar issues when employed as the anode in metal-sulfur batteries. Indeed, some inspiration for mechanism researches and strategies ...

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To establish a new model for estimating ground-level PM 2.5 concentration over Beijing, China, the relationship between aerosol optical depth (AOD) and ground-level PM 2.5 concentration was derived and analysed firstly. Boundary layer height (BLH) and relative humidity (RH) were shown to be two major factors influencing the relationship between AOD and ground-level PM 2.5 concentration. Thus, they are used to correct MODIS AOD to enhance the correlation between MODIS AOD and PM 2.5. When using corrected MODIS AOD for modelling, the correlation between MODIS AOD and PM 2.5 was improved significantly. Then, normalized difference vegetation index (NDVI), surface temperature (ST) and surface wind speed (SPD) were introduced as auxiliary variables to further improve the performance of the corrected regression model. The seasonal and annual average distribution of PM 2.5 concentration over Beijing from 2014 to 2016 were mapped for intuitively analysing. Those can be regarded as important references for monitoring the ground-level PM 2.5 concentration distribution. It is obviously that the PM 2.5 concentration distribution over Beijing revealed the trend of "southeast high and northwest low", and showed a significant decrease in annual average PM 2.5 concentration from 2014 to 2016.

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