ABSTRACT
Lithium-selenium batteries have emerged as a promising alternative to lithium-sulfur batteries due to their high electrical conductivity and comparable volume capacity. However, challenges such as the shuttle effect of polyselenides and high-volume fluctuations hinder their practical implementation. To address these issues, we propose synthesizing Fe-CNT/TiO2 catalyst through high-temperature sintering of an amalgamated nanoarchitecture of carbon nanotubes decorated metal-organic framework (MOF) and MXene, optimized for efficient selenium hosting, leveraging the distinctive physicochemical properties. The catalytic features inherent in the porous Se@Fe-CNT/TiO2 nanoarchitecture were instrumental in promoting efficient ion and electron transport, and lithium-polyselenide kinetics, while its inherent porosity could play a crucial role in inhibiting electrode stress during cycling. This nanoarchitecture exhibits remarkable battery performance, retaining 99.7% of theoretical capacity after 425 cycles at 0.5 C rate and demonstrating 95.8% capacity retention after 2000 cycles at 1 C rate, with â¼100% Coulombic efficiency. Additionally, the Se@Fe-CNT/TiO2 electrode exhibited an impressive recovery of 297.5 mAh/g (97.9%) capacity after undergoing 450 cycles at a charging rate of 10 C and a discharging rate of 1 C. This synergistic integration of MOF- and MXene-derived materials unveils new possibilities for high-performance and durable LSeBs, thus advancing electrochemical energy storage systems.
ABSTRACT
Selenium-based electrodes have garnered attention for their high electrical conductivity, compatibility with carbonate electrolytes, and volumetric capacity comparable to sulfur electrodes. However, real-time application is hindered by rapid capacity deterioration from the "shuttle effect" of polyselenides and volume fluctuations. To address these challenges, a hybrid Se@ZIF-67/Mo-MXene-derived (Se@Co-NC/Mo2C) nanoarchitecture is developed via an economically viable in situ electrostatic self-assembly of ZIF-67 and Mo2C nanosheets. The catalytic effects and porous framework of Co-NC/Mo2C enhance electrode attributes, promoting superior adsorption and conversion of lithium polyselenides and facile ion/electron transport within the electrode, resulting in stable electrochemical performance. Lithium-selenium batteries (LSeBs) exhibit remarkable characteristics, boasting high specific capacity and exceptional durability. The Se@Co-NC/Mo2C electrode delivers a reversible capacity of 503.5 mAh g-1 at 0.5 C with 98% capacity retention, 100% Coulombic efficiency, and exceptional cyclic durability through 8600 cycles. In sustainability tests at 10C/1C charging/discharging, the Se@Co-NC/Mo2C electrode demonstrates an optimistic and stable capacity of ≈370.6 mAh g-1 with 93% capacity retention at the 3100th cycle in a carbonate-based electrolyte and ≈181.3 mAh g-1 with 92% capacity retention after 5000 cycles in an ether-based electrolyte, indicating exceptional stability for practical rechargeable batteries. This cost-effective and efficient approach holds significant potential for high-performance and durable LSeBs.
