Metal Oxide Interlayer for Long‐Lived Lithium–Selenium Batteries

Abstract

A lithium–selenium (Li‐Se)‐alkali activated carbon hybrid cell with a tungsten oxide interlayer is implemented for the first time. The Se hybrid at a Se loading of 70 % in the full Li–Se cell delivers a large reversible capacity of 625 mA h gSe−1, in comparison with 505.8 mA h gSe−1 achieved for the pristine Se cell. This clearly shows the advantage of the carbon in improving the capacity of the Li‐Se cell. A tungsten oxide interlayer is drop‐cast over the battery separator to further circumvent the issues of polyselenide dissolution and shuttle, which cause severe capacity fading. The oxide layer conducts Li ions, as evidenced from the Li‐ion diffusion coefficient of 4.2×10−9 cm2 s−1, and simultaneously blocks the polyselenide crossover, as it is impermeable to polyselenides, thereby reducing the capacity fading with cycling. The outcome of this unique approach is reflected in the reversible capacities of 808 and 510 mA h gSe−1 achieved for the Li‐oxide@separator/Se‐alkali activated carbon cell before and after 100 cycles, respectively, thus demonstrating that carbon and oxide can efficiently restrict the capacity fading and improve the performances of Li‐Se cells.

Advanced design of cathodes and interlayers for high‐performance lithium‐selenium batteries

“…To further optimize the electrochemical performance of Li‐Se cells by chemical effects, metal oxides or carbides were coated on the separators 85 . Typically, 2D MXene nanosheets with atomic ultrathin thickness were reported to assemble into MXene‐based film interlayer for Li‐Se batteries.…”

“…To further optimize the electrochemical performance of Li-Se cells by chemical effects, metal oxides or carbides were coated on the separators. 85 Typically, 2D MXene nanosheets with atomic ultrathin thickness were reported to assemble into MXene-based film interlayer for Li-Se batteries. Specifically, 2D structures can physically block the diffusion of PSes to Li anode side, the polar functional groups on the MXene surfaces can chemically anchor PSes, and conductive MXene nanosheets can greatly reduce the voltage polarization of corresponding Li-Se batteries.…”

Versatile Graphitized Carbon Nanofibers in Energy Applications

“…Research efforts concerning the cathode materials for LIBs has been mostly concentrated on transition metal oxides and sulfides, such as V 2 O 5 and FeS 2 , and lithium-transition metal oxides, such as LiFePO 4 . 137,138 However, the shortcomings of V 2 O 5 include a low Li-ion diffusion coefficient besides intrinsically unsatisfactory electronic conductivity and its lower cycling stability as well as shorter cycle life. 139 The V 2 O 5 nanosheets anchored onto graphitized CNFs (V 2 O 5 @G-CNFs) were utilized directly as free-standing composite cathodes (prepared from PAN through the catalytic effect of FeO x acquired from Fe(acac) 3 ), 54 and graphitized CNFs (G-CNFs) showed 5 × 10 4 -fold superior conductivity compared to amorphous CNFs, suggesting faster kinetics.…”

Versatile Carbon Nanofiber-Based Sensors

“…23 There are various routes for the synthesis of CNFs, which include chemical vapor deposition, electrospinning, drawing, templating, and phase separation. 29 CNFs have edge planes and graphite planes showing great potential for surface modifications to build functional hybrids that find applications as nanodevices, 30 in sensing, 31 in biomedicine, in energy storage, 32 as batteries, 33 as supercapacitors, 34 in energy applications, 35 in fuel cells or solar cells, 36,37 in drug delivery, 37 and in environmental science areas. 38 This review is organized as follows: Section 1 gives a general introduction to CNFs and their different forms and properties.…”