Stable immobilization of lithium polysulfides using three-dimensional ordered mesoporous Mn_(2)O_(3) as the host material in lithium-sulfur batteries

Lithium-sulfur batteries(LSBs)have drawn significant attention owing to their high theoretical discharge capacity and energy density.However,the dissolution of long-chain polysulfides into the electrolyte during the charge and discharge process(“shuttle effect”)results in fast capacity fading and inferior electrochemical performance.In this study,Mn_(2)O_(3)with an ordered mesoporous structure(OM-Mn_(2)O_(3))was designed as a cathode host for LSBs via KIT-6 hard templating,to effectively inhibit the polysulfide shuttle effect.OM-Mn_(2)O_(3)offers numerous pores to confine sulfur and tightly anchor the dissolved polysulfides through the combined effects of strong polar-polar interactions,polysulfides,and sulfur chain catenation.The OM-Mn_(2)O_(3)/S composite electrode delivered a discharge capacity of 561 mAh g^(-1) after 250 cycles at 0.5 C owing to the excellent performance of OM-Mn_(2)O_(3).Furthermore,it retained a discharge capacity of 628mA h g^(-1) even at a rate of 2 C,which was significantly higher than that of a pristine sulfur electrode(206mA h g^(-1)).These findings provide a prospective strategy for designing cathode materials for high-performance LSBs.

Modification strategies improving the electrochemical and structural stability of high-Ni cathode materials

With the increasing spotlight in electric vehicles,there is a growing demand for high-energy-density batteries to enhance driving range.Consequently,several studies have been conducted on high-energy-density LiNi_(x)Co_(y)Mn_(z)O_(2)cathodes.However,there is a limit to permanent performance deterioration because of side reactions caused by moisture in the atmosphere and continuous microcracks during cycling as the Ni content to express high energy increases and the content of Mn and Co that maintain structural and electrochemical stabilization decreases.The direct modification of the surface and bulk regions aims to enhance the capacity and long-term performance of high-Ni cathode materials.Therefore,an efficient modification requires a study based on a thorough understanding of the degradation mechanisms in the surface and bulk region.In this review,a comprehensive analysis of various modifications,including doping,coating,concentration gradient,and single crystals,is conducted to solve degradation issues along with an analysis of the overall degradation mechanism occurring in high-Ni cathode materials.It also summarizes recent research developments related to the following modifications,aims to provide notable points and directions for post-studies,and provides valuable references for the commercialization of stable high-energy-density cathode materials.

Effects of dietary supplementation of bacteriophage cocktail on health status of weanling pigs in a non-sanitary environment

Background The study evaluated the effects of bacteriophage cocktail(BP)and ZnO administered during weaning time for piglets exposed to a non-sanitary environment.The bacteriophages were designed to eliminate Escherichia coli(K88,K99 and F41),Salmonella(typhimurium and enteritidis),and Clostridium perfreingens(types A and C).Forty 21-day-old crossbreed piglets were assigned to four treatments,including the PC(sanitary environment),NC(nonsanitary environment),BP(NC plus 108 pfu/kg BP),and ZO(NC plus 2,500 mg/kg ZnO).Piglets in the NC,BP and ZO were kept in a non-sanitary environment for 14 d,which was contaminated with the feces of infected pigs.Results Pigs in the BP and ZO treatments had a higher final body weight compared with the NC.The NC treatment showed the highest concentration of inflammatory cytokines including interleukin(IL)-1β,IL-6 and tumor necrosis factor-αin the plasma.The administration of BP and ZO showed lower myeloperoxidase concentrations compared with the NC.The NC treatment showed a lower concentration of superoxide dismutase in serum compared with the PC.Among the treatments in non-sanitary environment,the NC treatment showed a higher concentration of malondialdehyde compared with the ZO.The PC treatment showed a lower concentration of butyric acid in the feces compared with the BP treatment.Among non-sanitary treatments,the villus height in the duodenum was greater in the BP and ZO compared with the NC.The lower abundance of Proteobacteria phylum was observed in the BP and PC treatments compared with the NC.The highest relative abundance of Eubacterium was recorded in the BP treatment.The abundance of Megasphaera and Schwartzia was higher in the NC pigs compared with the BP piglets.The abundance of Desulfovibrio was lower in the supplemented treatments(BP and ZO)compared with non-supplemented(NC and PC).The abundance of Cellulosilyticum genera was higher in the BP and ZO treatments rather than in the NC.The piglets in the NC treatment had the highest abundance of Escherichia-Shigella,followed by the PC and ZO treatments.Conclusion In conclusion,these results suggest that the supplementation of bacteriophage cocktail could effectively control Proteobacteria phylum,Clostridium spp.and coliforms population and mitigated the adverse influences of weaning stress in piglets.

Iron sulfides with dopamine-derived carbon coating as superior performance anodes for sodium-ion batteries

High energy ball-milled iron sulfides with thin carb on layer coati ng(BM-FeS/C composites)were prepared by the simple and econo mical process.Ball-milled process,followed by carb on coati ng,reduced the particle size and increased the electrical con ductivity.Whe n employed as sodium-ion battery ano des,BM?F eS/C composites showed extremely high electrochemical performa nee with reversible specific capacity of 589.8 mAh·g^-1 after 100 cycles at a current density of 100 mA·g^-1.They also exhibited superior rate capabilities of 375.9 mAh·g^-1 even at 3.2 Ag^1 and 423.6 mAh·g^-1 at 1.5 Ag_1.X-ray absorptio n near edge structure an alysis con firmed the electrochemical pathway for con version reaction of BM-FeS/C composites.