TiO₂/GO-coated functional separator to suppress polysulfide migration in lithium–sulfur batteries

Abstract

Lithium–sulfur batteries render a high energy density but suffer from poor cyclic performance due to the dissolution of intermediate polysulfides. Herein, a lightweight nanoporous TiO2 and graphene oxide (GO) composite is prepared and utilized as an interlayer between a Li anode and a sulfur cathode to suppress the polysulfide migration and improve the electrochemical performance of Li/S batteries. The interlayer can capture the polysulfides due to the presence of oxygen functional groups and formation of chemical bonds. The hierarchically porous TiO2 nanoparticles are tightly wrapped in GO sheets and facilitate the polysulfide storage and chemical absorption. The excellent adhesion between TiO2 nanoparticles and GO sheets resulted in enhanced conductivity, which is highly desirable for an efficient electron transfer process. The Li/S battery with a TiO2/GO-coated separator exhibited a high initial discharge capacity of 1102.8 mAh g−1 and a 100th cycle capacity of 843.4 mAh g−1, which corresponds to a capacity retention of 76.48% at a current rate of 0.2 C. Moreover, the Li/S battery with the TiO2/GO-coated separator showed superior cyclic performance and excellent rate capability, which shows the promise of the TiO2/GO composite in next-generation Li/S batteries.

Inhibition of Polysulfide Shuttles in Li–S Batteries: Modified Separators and Solid‐State Electrolytes

“…Zhang et al [ 63 ] coated graphene oxide (GO) sheets with oxygen functional groups and TiO 2 nanoparticles on separators to help form chemical bonds with polysulfides. The formation of Ti–S and S–O–C bonds suggested the coating material was chemically adsorbed with polysulfides.…”

“…GO and RGO are usually combined with metal oxides because metal oxides have a strong polar surface exposing numerous unsaturated anions (O 2− ) and metal cations, thus having the ability to form polar‐polar bonding with polysulfides. The reported oxides applied as coatings cover MnO, [ 66 ] ZnO, [ 67,68 ] ZrO, [ 69 ] TiO, [ 70 ] MnO 2 , [ 71–74 ] TiO 2 , [ 63,75,76 ] CeO 2 , [ 77 ] SnO 2 , [ 78 ] MoO 3 , [ 79 ] In 2 O 3 , [ 80 ] La 2 O 3 , [ 81 ] Y 2 O 3 , [ 82 ] Al 2 O 3 , [ 32,83–85 ] Nb 2 O 5 , [ 86 ] Fe 3 O 4 , [ 64 ] NiCo 2 O 4 , [ 87 ] and MgAl 2 O 4 . [ 88 ]…”

All‐Purpose Electrode Design of Flexible Conductive Scaffold toward High‐Performance Li–S Batteries

“…The UV‐vis spectrum of the resulting Li 2 S 6 solution exhibits a weakened peak at around 280 and 415 cm −1 , implying a remarkable decrease of LiPS content after adsorption. In addition, in the Fourier transform infrared (FTIR) spectra of Li 2 S 6 ‐CoNi@PNCFs (Figure S9, Supporting Information), the peaks at 801, 740, and 450 cm −1 can be attributed to the SOC, SN, and NiS stretching, [ 52–54 ] respectively, further confirming the chemical bonding of Li 2 S 6 on CoNi@PNCFs surface. Moreover, the interaction between LiPS and CoNi@PNCFs was also studied by XPS analysis (Figure 3e).…”

Porous Fiber Processing and Manufacturing for Energy Storage Applications

“…Porous materials including nanoporous fibers have found various applications. One of the most important applications is for energy storage devices for example, capacitors [117][118][119][120][121][122][123][124][125][126][127][128][129][130][131] and rechargeable batteries [132][133][134][135][136][137]. Another important branch of applications is environment protection related.…”