ABSTRACT
The development of energy storage devices with high energy conversion ef›ciency is essentialforeffectiveuseofenergy.Itisidealthatexcessenergyisstoredandthen usedasneeded.Atpresent,lithium-ionbatteriesareinthemainstreamofsubstantial batterydevelopment,whichhasbeenstartedfromlead-acidbatteriesthroughthe developmentandimprovementofnewelectrodeandelectrolytematerials.Inboth gravimetric and volumetric energy densities, lithium-ion batteries are remarkably superiortootherrechargeablebatteries.Hence,lightandportablelithium-ionbatterieshavebeenusedaspowersourcesinvariouskindsofelectricdevices.Inrecent years,theyareusedforlarge-scaleapplicationssuchaselectricvehiclesandcogenerationsystems.Theexcellentenergydensitiesoflithium-ionbatteriesaremainly due to high voltage of more than 3 V. This is achieved by using organic electrolyte solutions,inwhichcathodematerialswithhighpotentialsandanodematerialswith lowpotentialscanbeused.Actually,otherrechargeablebatterieshavebeendevelopedbasedonaqueouselectrolytesolutionsandtheirvoltagesarestronglylimited by a thermodynamic stability window of water (1.23 V).
