Polyhydroxy Urethanes and Carbonates Bearing Bio-Based Solid Electrolyte for Solid-State Lithium Batteries

With higher energy density, flexibility, safe operation at both room temperature as well as high temperature, solid-state batteries technology has been strongly looked upon as superior diversion from conventional liquid electrolytes-based lithium batteries. Among various other class of polymers, there is strong need to focus on sustainable and yet better alternatives other than most researched polyethylene oxide (PEO). Poly(hydroxyurethanes) (PHU) owing to their high degree of structural tunability can be interesting candidates for Solid polymer electrolyte (SPE). Here, we synthesized bio-based PHU networks by facile ring-opening polymerization of carbonated soybean oil (CSBO) without catalyst. The existence of polyether and polyester provides the PHU network with soft segments while urethane linkage with hard segments. The lower T g with higher thermal stability widespread its application at elevated temperature without melting and significant degradation. PHU shows remarkable adhesive properties to the surface of metal speculating better interfacial contact and stability. The electrochemical investigations exhibited decent ionic conductivity (> 10 -4 at 60 o C), electrochemical stability window (ESW > 4.5 V vs. Li/Li + ) and transport properties allowing it to be explored for high voltage cathodes. Lithium ferrophosphate (LiFePO 4 ) cells with PHU also demonstrated promising charge-discharge (> 100 mAhg -1 at 60 o C) with the li-metal anode. The attempt to develop bio-based batteries materials are much required added step toward green and clean energy for a sustainable future.