Preparation And Electrochemical Performances Investigation Of Cathode Material For Lithium-ion Batteries

In this paper,some works about LIBs have been introduced,including lithium vanadium phosphate（LVP）synthesis,modified,and pilot produce,full cell design and its performances investigation,and failure analysis of high capacity manganese rich（HCMR）cathode material.The details are:Synthesize of LVP via in-situ fast sol-gel method,lithiation method,and ball-milling assist microwave method,separately.The LVP prepared via in-situ fast sol-gel method shows the particle size about 30¹00nm,with electronic conductivity about 1.0×10-5 S cm^-1 and ionic conductivity about 10^-7 cm2 s-1.It presents 77.52% of its theoretic capacity even at 50 C discharge rate.To avoid the agglomeration of LVP due to the absence of lithium,we prepare the LVP via a lithiation method via two steps: 1)synthesize of VP precursor,and 2)lithiated the VP to get the LVP.The prepared LVP with particle size about 50 nm presents the discharge capacity of 130 mAh/g.What is more,we also synthesized LVP via a ball-milling assist microwave method using microwave irritation to replease the high temperature and longtime sintering process.Modify LVP via coating and doping.The chitosan and porphyrin are firstly separately introduced as carbon source to synthesis LVP/C composites.The LVP/C prepared using chitosan as carbon source presents the discharge capacity of 91.14 mAh/g at 50 C discharge rate.The LVP/C using porphyrin as carbon source delivers the best electrochemical performances with 10% amount of porphyrin,and the flower-like LVP composed with nanoplates and nanofibers can be obtained with 15% amount porphrrin.LVP/C was synthesized firstly using inorganic carbon with different demensions（0D super P,1D CNT,2D graphene,and 3D graphite）as carbon sources.High performance hybrid phase Li₂NaV₂（PO₄）₃ composite consist of rhombohedral Li₃V₂（PO₄）₃（60.9%）,rhombohedral Na3V₂（PO₄）₃（31.6%）and monoclinic Li₃V₂（PO₄）₃（7.5%）is successfully synthesized via a sol-gel method.The H-LNVP delivers 92.2% of its total capacity at the plateau around 3.7V.The electronic and ionic conductivity can be improved via nickel-doping.Pilot produce of LVP and investigated the electrochemical performance for full cell base on LVP cathode.The LVP//LVP Li-ion vanadium battery（MLP-323850-200 mAh soft pack battery）was successfully assembled using LVP as both cathode and anode materials,and its charge/discharge theory is investigated.The LVP//Graphite battery（MLP-323850-300 mAh soft pack battery）has also investigated.Besides,the LVP//LTO battery is firstly composed and investigated.The rate performance,low and high temperature performance,and safety performance of LIBs（1380120-8Ah）with two different electrolytes are investigated.The electrochemical performances of HCMR are investigated and its failure analysis is performed.