Lithium vanadium phosphate LVP

Lithium vanadium phosphate is a kind of polyanionic anode material, which has the advantages of good stability, high safety, high theoretical capacity, high operating voltage and low price.
Lithium vanadium phosphate is a monoclinic structure compound with a higher positive lithium ion diffusion system and a higher discharge voltage (3.6/4.1V). At the same time, due to the addition of carbon in the lithium vanadium phosphate complex, the overall energy density and safety are high, which can not only exclude the shortcomings of lithium cobalt acid and lithium iron phosphate, but also improve the electrical conductivity [1]. However, vanadium material has the disadvantages of difficult extraction of precursor, high energy loss and high toxicity, so it is very important to analyze the application of graphene in the preparation of lithium vanadium phosphate for lithium ion batteries.
Lithium vanadium phosphate cationic and anion doping
On the one hand, the lithium vanadium phosphate/graphene complex crystal is a three-dimensional framework, which mainly includes phosphate tetrahedron and octahedron. Since lithium ions can be freely diffused within the crystal during the charge and discharge process, in order to ensure the electrochemical performance of lithium vanadium phosphate/graphene, the lithium ion diffusion channel in lithium vanadium phosphate materials can be further expanded by adjusting the number of cations or anions of lithium vanadium phosphate/graphene. The commonly used lithium vanadium phosphate/graphene modified cations are mainly manganese ions, barium ions, chromium ions and antimony ions. Taking chromium ion doping modification as an example, lithium carbonate, chromium acetate, ammonium hydrogen phosphate and ammonium metavanadate can be weighed according to the measurement ratio of house type in previous experiments. The mixture is then incorporated into 80mL of deionized water and the acid saturated solution is gradually added. After full stirring, adjust the pH to 7.0 with ammonia. The mixture was then placed in a water bath heated stirring instrument (80°C/3.5h) and an oven (80°C/10h). The modified material is cooled to room temperature in argon and then ground. By adjusting the proportion of chromium acetate, it can be concluded that with the increase of the proportion of chromium acetate, the diffraction peak crystal plane spacing of lithium vanadium phosphate material increases gradually, indicating that the material modification is successful. On the other hand, in the anionic doping of lithium vanadium phosphate/graphene, the main doped materials are chloride ions, fluorine ions and boric acid ions. Taking the addition of chloride ions as an example, the materials of lithium chloride, ammonium hydrogen phosphate, lithium carbonate and ammonium metavanadate can be classified according to the stoichiometric ratio.