Synergistic Ultrathin Functional Polymer-Coated Carbon Nanotube Interlayer for High Performance Lithium–Sulfur Batteries

Abstract

Lithium-sulfur (Li-S) batteries have been intensively investigated as a next-generation rechargeable battery due to their high energy density of 2600 W·h kg(-1) and low cost. However, the systemic issues of Li-S batteries, such as the polysulfide shuttling effect and low Coulombic efficiency, hinder the practical use in commercial rechargeable batteries. The introduction of a conductive interlayer between the sulfur cathode and separator is a promising approach that has shown the dramatic improvements in Li-S batteries. The previous interlayer work mainly focused on the physical confinement of polysulfides within the cathode part, without considering the further entrapment of the dissolved polysulfides. Here, we designed an ultrathin poly(acrylic acid) coated single-walled carbon nanotube (PAA-SWNT) film as a synergic functional interlayer to address the issues mentioned above. The designed interlayer not only lowers the charge transfer resistance by the support of the upper current collector but also localizes the dissolved polysulfides within the cathode part by the aid of a physical blocking and chemical bonding. With the synergic combination of PAA and SWNT, the sulfur cathode with a PAA-SWNT interlayer maintained higher capacity retention over 200 cycles and achieved better rate retention than the sulfur cathode with a SWNT interlayer. The proposed approach of combining a functional polymer and conductive support material can provide an optimiztic strategy to overcome the fundamental challenges underlying in Li-S batteries.

Chemical Immobilization Effect on Lithium Polysulfides for Lithium–Sulfur Batteries

“…The organic polymers have widely been used for polysulfide immobilization due to abundant function groups on their surface and long chain . According to the former reports on conductive polymers (polyaniline (PAN), polythiophene (PTh), and PPy), proton doping is usually adopted because protons could perform as bridges to connect the polysulfide anions to polymers via H‐bonds.…”

Enhanced Cycling Performance for Lithium–Sulfur Batteries by a Laminated 2D g‐C3N4/Graphene Cathode Interlayer

“…To overcome this obstacle, an organic or inorganic interlayer is used between the cathode and the separator to trap dissolved polysulfide species and thus restrain the shuttle effect ,. There have been many efforts to apply interlayers of various structures and compositions—including conductive polymers, metal–organic frameworks (MOFs), transition‐metal sulfides,, oxides, and nitrides,, and carbonaceous materials—to improve the electrochemical performance of Li–S batteries. Conductive polymer‐type interlayers, such as polypyrrole (PPy), polyaniline (PANI), and poly(3,4‐ethylenedioxythiophene) (PEDOT), not only can generate N−S, O−S, S−S, and hydrogen bonds with lithium polysulfides but also can tightly adhere to the polymer separator surface.…”

Rechargeable Aluminum/Iodine Battery Redox Chemistry in Ionic Liquid Electrolyte

“…This shuttle effect of the polyiodide is very similar to that of sulfur in Li/S chemistry. [22][23][24][25][26][27] Therefore, the polyiodide shuttle effect can also be substantially prevented through host and electrolyte optimization. Further work on improving the physical/chemical properties of the host for better iodine utilization and absorbability of polyiodide is still ongoing.…”