KISTI Institutional Repository: Ab Initio Study of the Sodium Intercalation and Intermediate Phases in Na0.44MnO2 for Sodium-Ion Battery

KISTI repository

download0 view888

This item is licensed Korea Open Government License

dc.identifier.uri: http://www.ndsl.kr/ndsl/search/detail/article/articleSearchResultDetail.do?cn=NART62231258

dc.description.abstract: TheNa0.44MnO2structureisapromisingcathodematerialforsodiumionbatteriesduetoahighcapacity(130mAh/g)andgoodcycleperformance.Inthiswork,wepresenttheresultsofdensityfunctionaltheory(DFT)calculationsonthestructuralandelectrochemicalpropertiesofNa0.44MnO2,combinedwithexperiments.Sevenintermediatephasesandthetwo-phasereactionsamongthemwerefound,wherethecalculatedvoltageprofileagreedwellwithexperiments.WefoundthattheS-shapedtunnelisnotemptyinthedeintercalatedNa0.22MnO2structurebuthasapartialoccupancyofsodiumions.Thenewsodiumsiteswerefoundinalimitedsodiumcompositionrange(x=0.44.55)whichisattributedtotheelectrostaticinteractionsbetweensodiumionsandmanganeseatoms.TheasymmetriclatticeevolutioninNa0.44MnO2asafunctionofsodiuminsertion/deinsertionisshowntobeduetotheJahn？Tellereffects.Onthebasisofthisinterpretation,wesuggestthattheCrsubstitutionwillreducethevolumechangesignificantly.