Nano‐TiO2‐Grafted Carbon Sheet Interlayer for Li–S Battery

Abstract

Lithium–sulfur (Li–S) battery with high theoretical capacity and high energy density is considered to be a best alternative of Li‐ion battery. However, challenges associated with Li–S batteries are yet to be addressed effectively to enable their commercialization. Uncontrolled shuttling of polysulfides causes rapid capacity decay and low discharge capacity of the battery cell. To address such shuttling effect related to the polysulfide movement, nano‐TiO2‐grafted carbon sheet interlayer is introduced. Proposed material is synthesized by the combined sol–gel and hydrothermal processes. Rietveld analysis is done for the determination of phase(s) present in the material. These are anatase and rutile phases. Scanning and transmission microscopic studies reveal the morphological features of prepared material. Quantitative study of prepared material for its constituents is done by thermogravimetry analysis, which confirms the presence of 83% TiO2. An interlayer of 16 mm diameter is punched out and incorporated in a coin cell assembly. Cell assembled with interlayer shows superior electrochemical performance with initial discharge capacity of 839 mAh g−1 at 0.2 C rate and 63% capacity retention till 100th cycle. Diffusion studies reveal that insertion of interlayer controls the reaction kinetics and supports polar–polar interaction between interlayer and polysulfides.