Monoclinic Li3V2(PO4)3 is a promising cathode material with complex charge-discharge behavior.Previous structural investigation of this compound mainly focuses on local environments;while the reac-tion kinetics and the driving force of irreversibility of this material remain unclear.To fully understand the above issues,both the equilibrium and the non-equilibrium reaction routes have been systematically investigated in this study.Multiple characterization techniques including X-ray diffraction,variable tem-perature(spinning rate)and ex/in situ 7Li,31P solid state NMR have been employed to provide compre-hensive insights into kinetics,dynamics,framework structure evolution and charge ordering,which is essential to better design and application of lithium transition metal phosphate cathodes.Our results suggest that the kinetics process between the non-equilibrium and the quasi-equilibrium delithiation pathways from Li2V2(PO4)3 to V2(PO4)3 is related with a slow relaxation from two-site to one-site delithi-ation.More importantly,it has been demonstrated that the irreversibility in this system is not solely affected by cation and/or charge ordering/disordering,but mainly driven by framework structure distortion.

Hua Huo;Zeyu Lin;Guiming Zhong;Shuaifeng Lou;Jiajun Wang;Yulin Ma;Changsong Dai;Yueping Xiong;Geping Yin;Yong Yang

Key Laboratory of Materials for New Energy Conversion and Storage(Ministry of Industry and Information Technology),School of Chemistry and Chemical Engineering,Harbin Institute of Technology,Harbin 150001,Heilongjiang,China;State Key Laboratory for Physical Chemistry of Solid Surface and Department of Chemistry,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,Fujian,China;Xiamen Institute of Rare Earth Materials,Haixi Institutes,Chinese Academy of Sciences,Xiamen 361021,Fujian,China

能源化学

[1]Hua Huo;Zeyu Lin;Guiming Zhong;Shuaifeng Lou;Jiajun Wang;Yulin Ma;Changsong Dai;Yueping Xiong;Geping Yin;Yong Yang-.The origins of kinetics hysteresis and irreversibility of monoclinic Li3V2(PO4)3)[J].能源化学,2022(04):593-603

Li2V2,delithi

origins,kinetics,hysteresis,irreversibility,monoclinic,Li3V2,PO4,Monoclinic,promising,material,complex,discharge,behavior,Previous,structural,investigation,this,compound,mainly,focuses,local,environments,while,driving,force,remain,unclear,To,fully,understand,above,issues,both,equilibrium,reaction,routes,have,been,systematically,investigated,study,Multiple,characterization,techniques,including,ray,diffraction,variable,perature,spinning,situ,7Li,31P,solid,state,NMR,employed,provide,compre,hensive,insights,into,dynamics,framework,structure,evolution,which,essential,better,design,application,lithium,transition,metal,phosphate,cathodes,Our,results,suggest,that,process,between,quasi,delithiation,pathways,from,related,slow,relaxation,two,site,one,More,importantly,has,demonstrated,not,solely,affected,by,disordering,but,driven,distortion

0.608216