Advanced chemical strategies for lithium-sulfur batteries: A review

Lithium-sulfur(Li-S) battery has been considered as one of the most promising rechargeable batteries among various energy storage devices owing to the attractive ultrahigh theoretical capacity and low cost. However, the performance of Li-S batteries is still far from theoretical prediction because of the inherent insulation of sulfur, shuttling of soluble polysulfides, swelling of cathode volume and the formation of lithium dendrites. Significant efforts have been made to trap polysulfides via physical strategies using carbon based materials, but the interactions between polysulfides and carbon are so weak that the device performance is limited. Chemical strategies provide the relatively complemented routes for improving the batteries' electrochemical properties by introducing strong interactions between functional groups and lithium polysulfides. Therefore, this review mainly discusses the recent advances in chemical absorption for improving the performance of Li-S batteries by introducing functional groups(oxygen, nitrogen, and boron, etc.) and chemical additives(metal, polymers, etc.) to the carbon structures, and how these foreign guests immobilize the dissolved polysulfides.

Carbothermic reduction of vanadium titanomagnetite with the assistance of sodium carbonate

The carbothermic reduction of vanadium titanomagnetite concentrate(VTC)with the assistance of Na_(2)CO_(3)was conducted in an argon atmosphere between 1073 and 1473 K.X-ray diffraction and scanning electron microscopy were used to investigate the phase transformations during the reaction.By investigating the reaction between VTC and Na_(2)CO_(3),it was concluded that molten Na_(2)CO_(3)broke the structure of titanomagnetite by combining with the acidic oxides(Fe_(2)O_(3),TiO_(2),Al_(2)O_(3),and SiO_(2))to form a Na-rich melt and release FeO and MgO.Therefore,Na_(2)CO_(3)accelerated the reduction rate.In addition,adding Na_(2)CO_(3)also benefited the agglomeration of iron particles and the slag–metal separation by decreasing the viscosity of the slag.Thus,Na_(2)CO_(3)assisted carbothermic reduction is a promising method for treating VTC at low temperatures.

Superhydrophobic fluoride conversion coating on bioresorbable magnesium alloy——fabrication,characterization,degradation and cytocompatibility with BMSCs

A micro-nano structure CaF_(2)chemical conversion layer was prepared on fluoride-treated AZ31 alloy,then the composite fluoride conversion film(CaF_(2)/MgF_(2))was modified by stearic acid(SA)and fabricated a superhydrophobic surface.The fluoride-treated magnesium,fluoride conversion film and superhydrophobic coating were characterized by SEM,EDS,XRD and FTIR.The properties of coatings1 adhesion and corrosion resistance were evaluated via tape test and electrochemical measurement.The cytocompatibility of the MgF_(2),CaF_(2)and superhydrophobic CaF_(2)/SA surface was investigated with bone marrow-derived mesenchymal stem cells(BMSCs)by direct culture for 24 h.The results showed that the superhydrophobic fluoride conversion coating composed of inner MgF_(2)layer and the outer CaF_(2)/SA composite layer had an average water contact angle of 152°.SA infiltrated into the micro-nano structure CaF_(2)layer and formed a strong adhesion with CaF_(2)layer.Furthermore,the super-hydrophobic coating showed higher barrier properties and corrosion resistance compared with the fluoride conversion film and fluoride-treated AZ31 alloy.The BMSC adhesion test results demonstrated MgF_(2)CaF_(2)and CaF_(2)/SA coatings were all nontoxic to BMSC.At the condition of in direct contact with cells,MgF_(2)showed higher cell density and enhanced the BMSCs proliferation,while CaF_(2)and CaF_(2)/SA coating showed no statistically difference in cell density compared with glass reference but the CaF_(2)and CaF_(2)/SA coating were not conducive to BMSCs adhesion.

Recent advances in interlayer and separator engineering for lithium-sulfur batteries

Lithium-sulfur(Li-S)batteries have great potential in next-generation energy storage due to its high theoretical specific capacity and energy density.However,there are several challenges to the practical application of Li-S batteries including the growth of lithium dendrites and the shuttle effect of polysulfide.Introducing interlayeres(freestanding or coated on the separator)is an effective approach to reduce these obstacles and improve the electrochemical performance of Li-S batteries.In this review,we briefly summarize the interlayer materials and structures modified on both cathodic and anodic sides including(ⅰ)carbon-based materials,(ⅱ)polymers,(ⅲ)inorganic metal compounds,(iv)metal-organic frameworks,as well as(v)the novel separators in recent years.We also systematically address the fabrication processes,assembling methods,and functions of interlayers for enhancing the performance of Li-S batteries.Furthermore,the prospects and outlooks of the future development of advanced interlayers and separators are also presented.

Non-equilibrium kinetic separation of thulium,yttrium and erbium on the surface of freely rising oil droplets

It is difficult to achieve selective separation and enrichment of different rare earths from high abundance yttrium ores efficiently only dependent on their discrepancy in thermodynamic properties.The present work suggests a new strategy based on non-equilibrium kinetic separation of Er and Tm on the surface of freely rising oil droplets to control the separation order of Y.It is revealed that the mutual separation of Er/Tm is significantly promoted with the separation coefficient of 2.89 during the non-equilibrium extraction with the addition of diethylenetriaminepentaacetic acid(DTPA).The extraction sequence of Tm,Er and Y can be controlled as Tm>Y>Er,thus Y can be selectively enriched during the process of separation of Er and Tm,Such a sequence is subject to the controllable dissociation rates of RE(Ⅲ)-DTPA complexes and extraction abilities of P507 with the three RE(Ⅲ)ions.The dissociation rate is dependent on the stabilities of RE(Ⅲ)-DTPA complexes and follows the sequence ofY(Ⅲ)—DTPA Er>Y to Tm>Y>Er.

Insular Cortex is Critical for the Perception, Modulation,and Chronification of Pain

An increasing body of neuroimaging and electrophysiological studies of the brain suggest that the insular cortex（IC） integrates multimodal salient information ranging from sensation to cognitive-affective events to create conscious interoception. Especially with regard to pain experience, the IC has been supposed to participate in both sensory-discriminative and affective-motivational aspects of pain. In this review, we discuss the latest data proposing that subregions of the IC are involved in isolated pain networks： the posterior sensory circuit and the anterior emotional network. Due to abundant connections with other brain areas, the IC is likely to serve as an interface where cross-modal shaping of pain occurs. In chronic pain,however, this mode of emotional awareness and the modulation of pain are disrupted. We highlight some of the molecular mechanisms underlying the changes of the pain modulation system that contribute to the transition from acute to chronic pain in the IC.

500-mW cm^(-2)underwater Zn-H_(2)O_(2)batteries with ultrafine edge-enriched electrocatalysts

Aqueous metal-H_(2)O_(2)cells are emerging as power batteries because of their large theoretical energy densities and multiple application scenarios,especially in underwater environments.However,the peak power densities are less than 300 mW cm^(-2)for most reported metal-H_(2)O_(2)cells based on Mg/Al or their alloys due to the self-corrosion.Herein,we reported a Zn-H_(2)O_(2)cell with ultrafine bean-pod-like ZnCo/N-doped electrocatalysts that were synthesized via multifunctional single-cell-chain biomass.The electrocatalyst provides abundant active sites on the crinkly interface and offers a shortened pathway for electron/ion transfer due to the desired root-like carbon nanotube(CNT)arrays.Therefore,the optimized electrocatalyst exhibited outstanding oxygen reduction reaction(ORR)activity,with high E_(1/2)(0.90 V)and E_(onset)(1.01 V)values.More importantly,Zn-H_(2)O_(2)batteries achieve a record-breaking peak-power density of 510 mW cm^(-2)and a high specific energy density of 953 Wh kg^(-1).

Enhanced electrical properties and Vickers hardness of calcium bismuth niobate ceramics by W/Co substituted at B-site

Calcium bismuth niobate(CBN)ceramic,as a core element of high-temperature piezoelectric sensors,has attracted widespread attention due to its high Curie temperature within the class of Aurivillius compounds.However,CBN usually faces two shortcomings.poor piezoelectric constant and low resistivity.In this work,CBN-based ceramics with donor–acceptor ions(W/Co)co-substituted at B-site were prepared by solid-state reaction method,and structure–property relationship of ceramics was studied in detail.Co-substitution of W/Co ions effectively improved the electrical property and hardness of CBN ceramics.CaBi_(2)Nb_(1.91)(W_(2/3)Co_(1/3)T_(0.09)O_(9))exhibits enhanced electrical and mechanical properties including high resistivity of-10^(7)Ω·cm at 500℃,piezoelectric constant of-15.3 pC/N and hardness value of-3.57 GPa.These values are two orders of magnitude,over two times,and 1.36 times higher than those of pure CBN ceramic,respectively.This work provides a reference for exploring other bismuth-layered structural ceramics.

Herpetrione, a New Type of PPARα Ligand as a Therapeutic Strategy Against Nonalcoholic Steatohepatitis

Non-alcoholic fatty liver disease, especially nonalcoholic steatohepatitis (NASH), is a leading cause of cirrhosis and liver cancer worldwide;nevertheless, there are no Food and Drug Administration-approved drugs for treating NASH until now. Peroxisome proliferator-activated receptor alpha (PPARα) is an interesting therapeutic target for treating metabolic disorders in the clinic, including NASH. Herpetrione, a natural lignan compound isolated from Tibetan medicine Herpetospermum caudigerum, exerts various hepatoprotective effects, but its efficacy and molecular mechanism in treating NASH have not yet been elucidated. Here, we discovered that herpetrione lessened lipid accumulation and inflammation in hepatocytes stimulated with oleic acid and lipopolysaccharide, and effectively alleviated NASH caused by a high-fat diet or methionine-choline-deficient diet by regulating glucolipid metabolism, insulin resistance, and inflammation. Mechanistically, RNA-sequencing analyses further showed that herpetrione activated PPAR signaling, which was validated by protein expression. Furthermore, the analysis of molecular interactions illustrated that herpetrione bound directly to the PPARα protein, with binding sites extending to the Arm III domain. PPARα deficiency also abrogated the protective effects of herpetrione against NASH, suggesting that herpetrione protects against hepatic steatosis and inflammation by activation of PPARα signaling, thereby alleviating NASH. Our findings shed light on the efficacy of a natural product for treating NASH, as well as the broader prospects for NASH treatment by targeting PPARα.