CoSe2 nanoparticles-decorated carbon nanofibers as a hierarchical self-supported sulfur host for high-energy lithium-sulfur batteries

Beaded CoSe2-C Nanofibers for High-Performance Lithium–Sulfur Batteries

“…Subsequently, the fiber-like structure remains the same after selenization, the CoSe 2 /C BNF fibers decorate with uniformly-dispersed CoSe 2 nanoparticles (Figure 1g,h) on the surface, which originate from the reaction of the Co and Se metal. As reported, the CoSe 2 nanoparticles could serve as an effective trapping agent and a catalyst for LiPSs [12,37].…”

“…Sulfur has been intensively investigated as an environmentally friendly cathode material owing to its high theoretical specific capacity (1675 mAh g −1 ) [7], abundant reserves, and economical nature. Despite these advantages, the commercialization of Li-S batteries has been hindered by the following challenges: (1) The poor electrical conductivity of sulfur and Li 2 S/Li 2 S 2 results in poor rate capabilities of the active material, which makes it difficult for the reduction/oxidation reaction to be fully completed; (2) During the discharge process, the sulfur will react with lithium to form soluble long-chain lithium polysulfides (LiPSs, Li 2 S n , 4 ≤ n ≤ 8) at the beginning and then further reduce to insoluble Li 2 S. The soluble LiPSs could dissolve in the electrolyte, named the shuttle effect of LiPSs, resulting in low Coulombic efficiency and fast degradation of the battery capacity along with the cycles; (3) Large volume changes (80%) seriously compromise the stability of the electrode structure during charging and discharging processes, which may cause the collapse of the electrode structure and the loss of the active materials, leading to the deterioration of the cycling stability; (4) The uneven plating/stripping behavior of metal lithium causes the growth of lithium dendrites, which could puncture the separators and cause serious safety accidents [8][9][10][11][12].…”

“…The utilization of electrospun nanofibers could effectively solve this issue through constructing a one-dimensional electronic interconnection. In addition, the three-dimensional porous features formed by the interconnected nanofibers can alleviate the volume changes of the active materials and enlarge the contact area between the electrolyte and hosts [12,[33][34][35]. Overall, although certain progress has been achieved in the exploitation of high-performance sulfur-based cathodes, further effects are still necessary to push the use of Li-S batteries in practical applications [36].…”

Spontaneous Built‐In Electric Field in C3N4‐CoSe2 Modified Multifunctional Separator with Accelerating Sulfur Evolution Kinetics and Li Deposition for Lithium‐Sulfur Batteries

“…[ 25–28 ] Furthermore, CoSe 2 can also reduce the nucleation barrier of Li 2 S and promote the uniform deposition of Li 2 S due to its excellent catalytic activity. [ 29–32 ] In particular, the CoSe 2 derived from ZIF‐67 can provide abundant catalytic active sites for the conversion of LiPSs and contribute to the realization of high‐sulfur loaded LSBs. [ 26,29,33 ] Unfortunately, such CoSe 2 electrocatalysts are anchored to a 3D porous carbon framework and composed of many discontinuous nanoparticles, which are easy to agglomerate or even break up during continuous charge and discharge process.…”

“…[ 29–32 ] In particular, the CoSe 2 derived from ZIF‐67 can provide abundant catalytic active sites for the conversion of LiPSs and contribute to the realization of high‐sulfur loaded LSBs. [ 26,29,33 ] Unfortunately, such CoSe 2 electrocatalysts are anchored to a 3D porous carbon framework and composed of many discontinuous nanoparticles, which are easy to agglomerate or even break up during continuous charge and discharge process. [ 34 ] The structural instability of CoSe 2 would weaken its catalytic effect, thus affecting the LiPSs conversion reaction and destroying the cyclic stability of the LSBs.…”