ABSTRACT

Rechargeable lithium batteries are widely used as a major power source for daily-use portableelectricdevices.Typicalrechargeablelithiumbatteriesarecomposedofa metal-oxide-basedpositiveelectrode(e.g.,LiCoO2) and a graphite-based negative electrode,forwhichvariousmaterialshavebeenproposedtoincreasetheirenergy densities.Meanwhile,therecentconcernabouttheresourcelimitationsandenvironmentalburdenhascompelledustouseraremetal-freeandlessresource-intensive materials in the batteries, especially for the positive electrodes. Many attempts have been made to reduce the use of rare metals by partially replacing them with other abundantelements,forexample,partiallysubstitutingFeorMnforCo.Adifferent approachistototallyforgoanymetallicelementintheelectrodeactivematerials byreplacingthemwithredoxactiveorganiccompoundsthatessentiallycontainno scarcemetals.Usingtheseredoxactiveorganicmaterialswouldalleviatetherestrictions posed by the resource scarcity. The preparation processes of organic materials canbelessenergyintensiveaswellwhencomparedtoinorganicmaterialsbecause thelatterareusuallyprocessedathighertemperaturesthantheformer.Furthermore, wehaverecentlyrevealedthatcertainorganiccompoundscanworkasapositive electrodeactivematerialnotonlyinthelithiumsystemsbutalsoinsystemsinwhich sodium or magnesium ions are a charge carrier, providing the possibility of developing post-lithium rechargeable batteries (see Section 11.4).