Mechanistic Origin of the High Performance of Yolk@Shell Bi₂S₃@N-Doped Carbon Nanowire Electrodes

Abstract

High-performance lithium-ion batteries are commonly built with heterogeneous composite electrodes that combine multiple active components for serving various electrochemical and structural functions. Engineering these heterogeneous composite electrodes toward drastically improved battery performance is hinged on a fundamental understanding of the mechanisms of multiple active components and their synergy or trade-off effects. Herein, we report a rational design, fabrication, and understanding of yolk@shell Bi 2 S 3 @N-doped mesoporous carbon (C) composite anode, consisting of a Bi 2 S 3 nanowire (NW) core within a hollow space surrounded by a thin shell of N-doped mesoporous C. This composite anode exhibits desirable rate performance and long cycle stability (700 cycles, 501 mAhg −1 at 1.0 Ag −1 , 85% capacity retention). By in situ transmission electron microscopy (TEM), X-ray diffraction, and NMR experiments and computational modeling, we elucidate the dominant mechanisms of the phase transformation, structural evolution, and lithiation kinetics of the Bi 2 S 3 NWs anode. Our combined in situ TEM experiments and finite element simulations reveal that the hollow space between the Bi 2 S 3 NWs core and carbon shell can effectively accommodate the lithiation-induced expansion of Bi 2 S 3 NWs without cracking C shells. This work demonstrates an effective strategy of engineering the yolk@shell-architectured anodes and also sheds light onto harnessing the complex multistep reactions in metal sulfides to enable high-performance lithium-ion batteries.

Monolayer triphosphates MP3 (M = Sn, Ge) with excellent basal catalytic activity for hydrogen evolution reaction

“…The convergence criterion is set to be 10 -5 eV for the energy and 0.01 eV Å -1 for the force, respectively. 39,40 A vacuum at least 20 Å along the out-plane direction and/or vertical to the nanoribbon edge direction is adopted so that the interaction between periodic units can be neglected. The reciprocal space is sampled on the Gamma centered meshes of 3 × 3 × 1 supercell, ensuring a density larger than 10 Å -1 .…”

High performance columnar-like Fe2O3@carbon composite anode via yolk@shell structural design

“…For decades, lithium-ion batteries have been the best option to power portable electronics and electric vehicles due to their high energy density, large power density and long lifespan [1][2][3][4][5][6][7][8][9][10][11][12][13][14] . However, the need for higher energy and power density is causing commercial graphitic anodes to be inadequate due to their relatively low theoretical specific capacity ( ∼370 mAh g −1 ) and slow lithium ion diffusivity (less than 10 −6 cm 2 s −1 ) [15][16][17][18][19][20][21] .…”

“…Despite these incremental improvements, the high rate capability and long-term cycling stability is still unsatisfactory [35] . Specifically, capacity fade occurred during prolonged cycling still caused by volume changes during charge/discharge processes and the degradation of electrically conductive pathways [3,41] . Thus, it is highly desirable to develop uniquely designed nanostructured Fe 2 O 3 @C hybrids with attractive features like structural stability and constant contact between Fe 2 O 3 and C, even after repeated cycling, to overcome the negative effects of volume change and poor electrical conductivity.…”

A reduced graphene oxide–borate compound-loaded melamine sponge/silicone rubber composite with ultra-high dielectric constant

“…[14][15][16] The conductive network formed by conductive llers can usually improve the electrical properties of composites. Common conductive llers are metals, 17 carbon materials [18][19][20][21] (e.g., carbon black, fullerene, graphite, graphene, reduced graphene oxide (rGO), carbon nanotubes, carbon nanobers, and carbon nanowires), and conducting polymers. 22 Among them, graphene has large specic surface area, high aspect ratio, and excellent electrical properties and is currently a research hotspot for the preparation of functional polymer-based composites.…”