Enhanced Performance of Li-S Batteries By PANI Printing Method

Abstract

Lithium-sulfur (Li-S) batteries have received considerable attention, since their theoretical energy density (2500Wh kg-1) is ~7 times larger than those of the current LIBs (~387Wh kg-1) utilizing the unparalleled theoretical capacity of sulfur (1,675 mAh g-1). The practical application of Li-S cell is still limited mainly due to the low conductivity of sulfur (~10-30 S cm-1), the volumetric expansion up to 80% during the discharge and the dissolution of polysulfides resulting shuttling effect in the charge-discharge process. In the present investigation, we develop a printing method for enhancing the lithium sulfur batteries. PANI layer coated sulfur electrode was demonstrated by a simple printing method. The role of printed layer is confirmed by in-situ UV/Vs test. The PANI layer avoids the chronic issues previously reported in lithium-sulfur batteries. In particular, the printing method is able to enhance the lithium-sulfur cell and the printed layer plays an important role as an electrolyte-blocking layer, preventing the dissolution of polysulfides. In the printed sulfur electrode, the capacity retention was 96.4% with 99.6% of average Coulombic efficiency (1C cycle), and 105% of the original capacity was still retained with 99.3% of average Coulombic efficiency (0.1C cycle). This effect induces the stable cycling capacity of sulfur electrode. The strategy employed in this work to produce a uniform PANI layer printed onto electrode surface is also applicable to all of other sulfur electrode to develop stable cell that avoid the shuttling effect.