In Situ Imaging Polysulfides Electrochemistry of Li-S Batteries in a Hollow Carbon Nanotubule Wet Electrochemical Cell

Abstract

Understanding polysulfide electrochemistry is critical for mitigation of the polysulfide shuttle effect in Li-S batteries. However, in situ imaging polysulfides evolution in Li-S batteries has not been possible. Herein, we constructed a hollow carbon nanotubule (CNT) wet electrochemical cell that permits real-time imaging of polysulfide evolutions in Li-S batteries in a Cscorrected environmental transmission electron microscope. Upon discharge, sulfur was electrochemically reduced to long-chain polysulfides, which dissolved into the electrolyte instantly and were stabilized by Py 14 + cations solvation. Metastable polysulfides prove to be problematic for Li-S batteries, therefore, destabilizing the Py 14 + -solvated polysulfides by adding low polarized solvents into the electrolyte to weaken the interaction between Py 14 + cation and long-chain polysulfides renders a rapid polysulfides-to-Li 2 S transition, thus efficiently mitigating polysulfide formation and improving the performance of Li-S batteries dramatically. Moreover, the CNT wet electrochemical cell proves to be a universal platform for in situ probing electrochemistry of various batteries.

Confining ZnS/SnS2 Ultrathin Heterostructured Nanosheets in Hollow N‐Doped Carbon Nanocubes as Novel Sulfur Host for Advanced Li‐S Batteries

“…To this end, various hollow polar/nonpolar hosts toward efficient sulfur fixation have been well documented to achieve performance improvement of Li-S batteries. [8][9][10][11][12][13] Hollow carbon nanomaterials, such as carbon nanotubes/nanoboxes, [14][15][16][17] hollow carbon nanofibers/nanospheres, [12,18,19] and their hybrid forms, [20,21] have been long investigated as hosts for sulfur cathodes, resulting from their high electronic conductivity and large specific surface area. Unfortunately, nonpolar carbons are ineffective in confining soluble polar LiPSs within the cathode due to their weak physical interaction, and thus sulfur species gradually detach from the carbon matrix during long-term cycling.…”

Realigning the Chemistry and Parameterization of Lithium‐Sulfur Battery Models to Accommodate Emerging Experimental Evidence and Cell Configurations

“…Specifically, dissociation of polysulfide anions into constituent radical anions has been reported in many experimental papers. [16][17][41][42]45,[48][49][50] We take this dissociation reaction to be a reversible, non-charge transfer reaction occurring homogeneously in the electrolyte according to Equation (1). Because the reaction is presumed reversible and elementary as written, the forward and backward reaction rates are…”

“…Inclusion of the electrolyte chemistry shown in Equation (1) allows for the generation of S �À 3 radical, an electrolyte species widely observed in lithium sulfur battery studies. [41][42][43][44][45][46] By adding Equation (1), we can explore, for the first time, how this homogenous, non-chargetransfer dissociation reaction is linked to the discharge behavior of a lithium sulfur battery with state-of-art geometric and physicochemical parameters.…”

Advances in understanding and regulation of sulfur conversion processes in metal–sulfur batteries

“…Great advances have been achieved in developing high-performance LSBs with impressive values reported in the literature, such as cycle life of 2000 cycles, 209,210 high rate capability at 40C, 211,212 or high capacities of over 1200 mA h g À1 . 213,214 However, most of these studies were conducted using coin cell congurations with limited active materials and excessive amounts of electrolytes, which created a huge gap between the achievements in the lab and the expectations from the real world.…”