Composite electrolytes for lithium rechargeable batteries

The paper reviews and presents attributes of emerging polymer-ceramic compo site electrolytes for lithium rechargeable batteries. The electrochemical d ata of a diverse range of composite electrolytes reveal that the incorporat ion of a ceramic component in a polymer matrix leads to enhanced conductivi ty, increased lithium transport number, and improved electrode-electrolyte interfacial stability. The conductivity enhancement depends upon the weight fraction of the ceramic phase, annealing parameters, nature of polymer-cer amic system, and temperature. The ceramic additive also increases the effec tive glass transition temperature and thus decouples structural and electri cal relaxation modes which in turn increases the lithium transport number. The ceramic additives also provide a range of free energy of reactions with lithium. A few of the ceramic materials (MgO, CaO, Si3N4) have positive fr ee energy of reaction and they should not passivate lithium electrodes.