Search for: All records

Abstract 1D materials, such as nanofibers or nanoribbons are considered as the future ultimate limit of downscaling for modern electrical and electrochemical devices. Here, for the first time, nanofibers of a solid solution transition metal trichalcogenide (TMTC), Nb_1‐xTa_xS₃, are successfully synthesized with outstanding electrical, thermal, and electrochemical characteristics rivaling the performance of the‐state‐of‐the art materials for each application. This material shows nearly unchanged sheet resistance (≈740 Ω sq⁻¹) versus bending cycles tested up to 90 cycles, stable sheet resistance in ambient conditions tested up to 60 days, remarkably high electrical breakdown current density of ≈30 MA cm⁻², strong evidence of successive charge density wave transitions, and outstanding thermal stability up to ≈800 K. Additionally, this material demonstrates excellent activity and selectivity for CO₂conversion to CO reaching ≈350 mA cm⁻²at −0.8 V versus RHE with a turnover frequency number of 25. It also exhibits an excellent performance in a high‐rate Li–air battery with the specific capacity of 3000 mAh g⁻¹at a current density of 0.3 mA cm⁻². This study uncovers the multifunctionality in 1D TMTC alloys for a wide range of applications and opens a new direction for the design of the next generation low‐dimensional materials. 

Abstract Redox meditators (RMs) are soluble catalysts located in an electrolyte that can improve the energy efficiency (reduced overpotential) and cyclability of Li–oxygen (Li–O₂) batteries. In this work, 20 RMs within a Li–O₂system with dimethyl sulfoxide and tetraethylene glycol dimethyl ether electrolytes are studied and their electrochemical features such as redox potential, the separation of cathodic and anodic peaks, and their current intensities are measured using cyclic voltammetry (CV) experiments. Six RMs are selected as “primary” choices based on their electrochemical performance, and stability tests are then performed to examine their electrochemical responses after consecutive cycles. Moreover, galvanostatic cycling tests are performed within a Li–O₂battery system assembled with selected six RMs for real case consistency investigations. It is found that results from CV to galvanostatic cycling tests are consistent for halides and organometallic RMs, where the former exhibit much higher stability. However, the organic RMs show high reversibility in CV but low in battery cycling results. Density functional theory calculations are carried out to gain more understanding of the stability and redox potentials of the RMs. This study provides comparative information to select the most reliable RMs for Li–O₂batteries along with new fundamental understanding of their electrochemical activity and stability.