Pursuing rechargeable metal-ion batteries with greater energy density is attracting great attention due to increasing demand for energy storage, where alloying anodes can provide very high capacity. [1][2][3][4][5][6][7] This is particularly true since sodium and potassium ion battery technologies offer limited capacity and stability using classic carbon-based anodes compared to lithium ions. [8][9][10][11] However, alloying anodes are notorious for their severe capacity fading, which has hindered their practical applications. The failure mechanism of alloying anodes has always been ascribed to the large volumetric change (~300%) and/or the fragile solid electrolyte interphase (SEI). [12][13][14][15] This interpretation is popular because the pulverization of the alloy-based electrodes can be observed during the reactions. As a result, many strategies have been developed to overcome this issue. These strategies include nano-structural controlling, carbon modification, and improving electrical conductivity. Thus, many nanostructured alloys including particles, 16 fibers/tubes, 5,17 film/membrane, 18,19 and hierarchical material 20,21 are being explored to stabilize alloying anodes. Characteristic, conductive and/or protective materials such as carbon and artificial solid electrolyte interphase (SEI) have been also used to improve alloying anode capacities stabilities. [22][23][24][25] Herein we show that an unprecedented high capacity (>650 mAh g -1 ) and stability (>500 cycles) can be achieved in alloying anodes by simply tuning the electrolyte composition, without the need for nanostructural control, carbon modification, and/or SEI engineering. We confirm that the cation solvation structure (e.g., Na + , K + ), particularly the type and location of the anions present in the metal salt and solvents, plays a critical role in affecting the alloying anode performance. In addition, we present a new anionic model showing that the anion corrosion plays at least an equally important role in alloying anode stability as the volume variation and fragile SEI models. Moreover, we present a new reaction model for alloying anode to make the ASSOCIATED CONTENT Supporting Information. Experimental and simulation section. Figures S1-S17 and Table S1 are included.

The attractive features of KIBs include abundant potassium sources, and K + /K redox potential that is close to Li + / Li (−2.93 V vs −3.04 V) and even lower than −2.71 V of Na + /Na. [2] Therefore, KIBs have the potential to provide greater energy density at a lower cost. However, designing high capacity, stable, and safe electrodes for KIBs remains challenging. This is because the ionic radius of potassium (K +) is large, which can cause a low specific capacity and degrade stability of the electrode during the K + (de-)intercalation or reaction. [3] Although many kinds of cathodes with a large crystalline channel or durable conjugated structure (e.g., metal layered oxide, [4] polyanionic compound, [5] Prussian blue analogs, [6] organic materials [7]) are being hitherto developed, most reported capacities have been less than 150 mAh g-1. This low capacity of the cathodes presents a serious bottleneck for KIB development. [8] Alternatively, various high capacity anodes such as alloys, [9] transition-metal oxides/sulfides, [10] and MXene-based materials [11] bring new opportunities to design high-energy-density KIBs. Particularly, the alloying anodes can exhibit significantly higher capacity than classic carbon-based anodes (i.e., 280 mAh g-1 of graphite). [12] For example, the potassium storage capacity of metallic antimony (Sb) can reach as high as 660 mAh g-1 , which is close to the theoretical capacity of metal K (i.e., 687 mAh g-1). [13] But, the capacity suffers a severe capacity decay caused by the large volumetric change of Sb (≈300%). [9a] Although a variety of strategies including structural design (e.g., nanoparticles, [14] hollow spheres, [15] fibers, [9a] films, [13] and hierarchical structures [16]), carbon modification (e.g., Sb@NC, [17] Sb@CNFs, [13] Sb@Go, [18] Sb@CSN, [19] and Sb/C [20]), and SEI engineering [19] are being developed to stabilize the Sb anode, the capacity and stability still have a large room to be improved. Herein, we present a new approach of electrolyte engineering to stabilize bulk Sb anodes. Extremely high capacity of 628 mAh g-1 at the current density of 100 mA g-1 and a good rate capability of 305 mAh g-1 at the hash current density of 3 A g-1 can be achieved by varying the electrolyte composition (e.g., anions, solvent, and concentration). To our knowledge, this is the best electrochemical performance reported so far for Sb alloying anode in KIBs. Amazingly, this high capacity which remained stable for over 200 cycles, was achieved without the need for Alloying anodes exhibit very high capacity when used in potassium-ion batteries, but their severe capacity fading hinders their practical applications. The failure mechanism has traditionally been attributed to the large volumetric change and/or their fragile solid electrolyte interphase. Herein, it is reported that an antimony (Sb) alloying anode, even in bulk form, can be stabilized readily by electrolyte engineering. The Sb anode delivers an extremely high capacity of 628 and 305 mAh g-1 at current densities of 100 and 3...

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Potassium ion batteries (KIBs) are attractive alternatives to lithium-ion batteries (LIBs) due to their lower cost and global potassium sustainability. However, designing compatible electrolytes with the graphite anode remains challenging. This is because the electrolyte decomposition and/or graphite exfoliation (due to K + -solvent co-insertion) always exist, which is much harder to overcome compared to the case of LIBs due to the higher activities of K + . Herein, we report a general principle to design compatible electrolytes with graphite anode, where the K + can be reversibly (de-)intercalated. We find that the electrolyte composition is critical to determining the graphite performance, which can be tuned by the kind of solvent, anion, additives, and concentration. We present a new interfacial model to understand the variation in performance (i.e., K + (de-)intercalation, or K + -solvent co-insertion or decomposition). Our interfacial model is distinctly different from the solid electrolyte interphase (SEI) interpretation. This work offers new opportunities to design high-performance KIBs and potassium-ion sulfur batteries. Particularly, we present a new guideline to design electrolytes for KIBs and other advanced mobile (ion) batteries.

Sodium (ion) batteries are promising alternatives for lithium-ion batteries due to their lower cost caused by global sodium availability. However, the low Coulombic efficiency (CE) of the sodium metal plating/stripping process represents a serious issue for the Na anode, which hinders achieving higher energy density. Herein, we report that the Na+ solvation structure, particularly the type and location of the anions, plays a critical role in determining the Na anode performance. We show that the low CE results from anion-mediated corrosion, which can be tackled readily through tuning the anion interaction at the electrolyte/anode interface. Our strategy thus enables fast charging Na-ion and Na-S batteries with remarkable cycle-life. The presented insights differ from the prevailing interpretation that the failure mechanism mostly results from sodium dendrite growth and/or solid electrolyte interphase formation. Our anionic model introduces a new guideline for improving the electrolytes for metal (ion) batteries with greater energy density.

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Non-thermal plasma holds great potentials as an efficient, economical, and eco-friendly seed pretreatment method for improving the seed germination and seedling growth, but the mechanisms are still unclear. Therefore, a plant model organism Arabidopsis thaliana was used to investigate the physio-biochemical responses of seeds to non-thermal plasma at different treatment times by measuring the plant growth parameters, redox-related parameters, calcium (Ca2+) level and physicochemical modification of seed surface. The results showed that short-time plasma treatment (0.5, 1, and 3 min) promoted seed germination and seedling growth, whereas long-time plasma treatment (5 and 10 min) exhibited inhibitory effects. The level of superoxide anion (O2•−) and nitric oxide (NO) and the intensity of infrared absorption of the hydroxyl group were significantly higher in short-time plasma treated Arabidopsis seeds, and the level of hydrogen peroxide (H2O2) was remarkably increased in long-time plasma treated seeds, indicating that O2•−, ·OH, and NO induced by plasma may contribute to breaking seed dormancy and advancing seed germination in Arabidopsis, while plasma-induced H2O2 may inhibit the seed germination. The intensity of hydroxyl group and the contents of H2O2, malondialdehyde, and Ca2+ in Arabidopsis seedlings were obviously increased with the plasma treatment time. Catalase, superoxide dismutase, and peroxidase activities as well as proline level in short-time treated seedlings were apparently higher than in control. The etching effects of plasma on seed surface were dose-dependent, spanning from slight shrinkages to detached epidermis, which also significantly increased the oxidation degree of seed surface. Therefore, the improved activities of antioxidant systems, moderate ·OH, H2O2, and Ca2+ accumulation and seed surface modification induced by plasma all contribute to the enhanced seedling growth of Arabidopsis after short-time plasma treatment.

Potassium ion batteries (KIBs) are attracting great attention as an alternative to lithium-ion batteries due to lower cost and better global sustainability of potassium. However, designing electrolytes compatible with the graphite anode and addressing the safety issue of highly active potassium remains challenging. Herein, a new concept of using additives to engineer nonflammable electrolytes for safer KIBs is introduced. It is discovered that the additives, such as the ethylene sulfate (i.e., DTD), can make the electrolyte of 1.0 m potassium bis(fluorosulfonyl) imide in trimethyl phosphate compatible with graphite anode for the first time, without the need of concentrated electrolyte strategies. A new coordination mechanism of additives in the electrolyte is presented. It is shown that the additive can change the K + solvation structure and then determine the interfacial behaviors of K +-solvent on electrode interface, which are critical to affect the graphite performance (i.e., K +-solvent co-insertion, or K + (de-)intercalation). Then, an extremely high potassium storage capability is obtained in graphite electrode for potassium (ion) batteries, particularly the presented high-performance graphite|K 0.69 CrO 2 full battery fully demonstrates the practical application of this newly designed electrolyte. This additive-based strategy can offer more opportunities to tune the electrolyte properties and then serve for the more mobile ion battery system.