The Nickel-rich layered cathode materials charged to 4.5 V can obtain a specific capacity of more than 200 mAh g-1.However,the nickel-rich layered cathode materials suffer from the severe capacity fade during high-voltage cycling,which is related to the phase transformation and the surface sides reactions caused by the lattice oxygen evolution.Here,the simultaneous construction of a Mg,Ti-based surface integrated layer and bulk doping through Mg,Ti surface treatment could suppress the lattice oxygen evolution of Ni-rich material at deep charging.More importantly,Mg and Ti are co-doped into the particles surface to form an Mg2TiO4 and Mg0.5-xTi2-y(PO4)3 outer layer with Mg and Ti vacancies.In the constructed surface integrated layer,the reverse electric field in the Mg2TiO4 effectively suppressed the outward migration of the lattice oxygen anions,while Mg0.5-xTi2-y(PO4)3 outer layer with high electronic conductivity and good lithium ion conductor could effectively maintained the stability of the reaction interface during high-voltage cycling.Meanwhile,bulk Mg and Ti co-doping can mitigate the migration of Ni ions in the bulk to keep the stability of transition metal-oxygen(M-O)bond at deep charging.As a result,the NCM@MTP cathode shows excellent long cycle stability at high-voltage charging,which keep high capacity retention of 89.3％and 84.3％at 1C after 200 and 100 cycles under room and elevated temperature of 25 and 55℃,respectively.This work provides new insights for manipulating the surface chemistry of electrode mate-rials to suppress the lattice oxygen evolution at high charging voltage.

Fan Peng;Youqi Chu;Yu Li;Qichang Pan;Guangchang Yang;Lixuan Zhang;Sijiang Hu;Fenghua Zheng;Hongqiang Wang;Qingyu Li

Guangxi Key Laboratory of Low Carbon Energy Materials,School of Chemistry and Pharmaceutical Sciences,Guangxi Normal University,Guilin 541004,Guangxi,China;Guangxi New Energy Ship Battery Engineering Technology Research Center,Guangxi Normal University,Guilin 541004,Guangxi,China

能源化学

[1]Fan Peng;Youqi Chu;Yu Li;Qichang Pan;Guangchang Yang;Lixuan Zhang;Sijiang Hu;Fenghua Zheng;Hongqiang Wang;Qingyu Li-.Mg,Ti-base surface integrated layer and bulk doping to suppress lattice oxygen evolution of Ni-rich cathode material at a high cut-off voltage)[J].能源化学,2022(08):434-444

Mg2TiO4,xTi2

surface,integrated,bulk,doping,lattice,oxygen,evolution,rich,cathode,high,cut,off,voltage,Nickel,layered,materials,charged,obtain,specific,capacity,more,than,mAh,However,nickel,suffer,from,severe,fade,during,cycling,which,related,phase,transformation,sides,reactions,caused,by,Here,simultaneous,construction,through,treatment,could,deep,charging,More,importantly,are,doped,into,particles,Mg0,PO4,outer,vacancies,In,constructed,reverse,electric,field,effectively,suppressed,outward,migration,anions,electronic,conductivity,good,lithium,conductor,maintained,stability,interface,Meanwhile,mitigate,keep,transition,metal,bond,result,NCM,MTP,shows,excellent,long,retention,1C,after,cycles,under,room,elevated,temperature,respectively,This,work,provides,new,insights,manipulating,chemistry,electrode

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