Controllable synthesis of spherical Li3V2(PO4)3/C cathode material and its electrochemical performance

Spherical Li3V2(PO4)3/C (LVP/C) composites are successfully synthesized via two different spray-drying processes. XRD results reveal that some impurities, such as Na3V2(PO4)3, Li2NaV2(PO4)3 and Li4(P2O7), appear when sodium salt of carboxy methyl cellulose (CMC) acts as carbon source. SEM images show two different morphologies: solid spherical particles for LVP/C(A) prepared by adding CMC after pre-sintering, and hollow for LVP/C(B) prepared by adding CMC before pre-sintering. Compared to LVP/C(B), LVP(A) presents higher tap density and better electrochemical performance at any C-rate. Remarkably, another charge/discharge plateaus or anodic/cathodic peaks around 3.85 V are detected for both LVP/C(A) and LVP/C(B) electrodes, which is attributed to the formation of Li3−xNaxV2(PO4)3 or some other electrochemically active composites containing Na+. CMC addition sequence has a significant influence on morphology of Li3V2(PO4)3. Furthermore, acting as carbon source and Na dopant, CMC shows a notable effect on electrochemical behavior of Li3V2(PO4)3 cathode material.

Spherical Li3V2(PO4)3/C composites with carboxy methyl cellulose (CMC) as carbon source are successfully synthesized via two different spray-drying processes. Solid or hollow spherical morphology can be selectively attained by changing CMC addition sequence. CMC serves not only as carbon source but also for Na doping, which shows a notable effect on electrochemical behavior of Li3V2(PO4)3 cathode material.Figure optionsDownload as PowerPoint slideHighlights
► Controllable synthesis of spherical Li3V2(PO4)3/C (LVP/C) composites was carried out via spray-drying method.
► Carboxy methyl cellulose (CMC) was used as carbon source and also as Na dopant.
► Solid and hollow spherical particles can be selectively attained by controlling preparation condition.
► Effect of CMC on the performance of Li3V2(PO4)3 was carefully investigated.