Sodium layered oxide with anion redox activity (SLO-A) stands out as a promising cathode material for sodium-ion batteries due to its impressive capacity and high voltage resulting from Mn- and O-redox processes. However, the SLO-A faces significant challenges in cycling stability and rate performance, primarily due to the poor reversibility and sluggish kinetics of the O-redox. In this study,a novel Ti-doped material, Na 2/3 Li 2/9 Mn 53/72 Ti 1/24 O 2 (NLMTO), exhibiting remarkable characteristics such as a notable rate capacity (130 mAh g −1 at 3C, where 1C equals 200 mA g −1 ) and excellent cycling retention (85.4% after 100 cycles at 0.5C) is introduced. Employing electrochemical differential analyses, the contributions to the superior performance arising from the Mn- and O-redox processes are quantitatively delineated. The optimized performance of NLMTO is attributed, in part, to the enhanced stability of both bulk and interface structures. The introduction of Ti through substitution not only contributes to this stability but also allows for the fine-tuning of the material's electron configurations. This is achieved by augmenting the density of states near the Fermi energy level, as well as elevating the O 2p and Mn 3d orbits. This research advances sodium-ion battery technology.
Recently, the influence of metal oxide nanoparticles (NPs) on methanogenesis in anaerobic digestion has drawn much attention, however, the changes in NPs and functioning consortia within the methanogenic community are usually not investigated. Therefore, the methanogenesis performance, NPs transformation and methanogenic community development in anaerobic digester sludge under MnO 2 NP supplementation were demonstrated in this study. MnO 2 NPs (400 mg/gVSS) stimulated the methane (CH 4 ) yield by 42% for a final CH 4 proportion of 81.8% of the total gas production. Meanwhile, the coenzyme F 420 and INT-electron transport system activities showed positive correlation with MnO 2 concentration. Microbial Mn reduction and oxidation occurred in conjunction with methanogenesis, resulting in transformation of the shape of the MnO 2 NPs from wire-like to globular particles. Microbial community analysis indicated that the relative abundances of genera Methanobacterium , Methanosaeta, and Methanosarcina were higher in the presence of MnO 2 NPs. Moreover, a new and different crucial synergy within the methanogenic community was formed with low-abundance consortia driving Mn respiration coupled to methanogenesis in anaerobic digestion. To our knowledge, this is the first report on transformation of metal oxides NPs combined with syntrophic community development in studies focusing on methanogenesis in response to NPs.
危险品化学品经营许可证（带存储）