Single-Particle Performances and Properties of LiFePO4 Nanocrystals for Li-Ion Batteries

摘要

It has been recently reported that the solution diffusion, efficiency porosity, and electrode thickness can dominate the high rate performance in the 3D-printed and traditional LiMn0.21Fe0.79PO4 electrodes for Li-ions batteries. Here, the intrinsic properties and performances of the single-particle (SP) of LiFePO4 are investigated by developing the SP electrode and creating the SP-model, which will share deep insight on how to further improve the performance of the electrode and related materials. The SP electrode is generated by fully scattering and distributing LiFePO4 nanoparticles to contact with the conductive network of carbon nanotube or conductive carbon to demonstrate the sharpest cyclic voltammetry peak and related SP-model is developed, by which it is found that the interfacial rate constant in aqueous electrolyte is one order of magnitude higher, accounting for the excellent rate performance in aqueous electrolyte for LiFePO4. For the first time it has been proposed that the insight of pre-exponential factor of interface kinetic Arrhenius equation is related to desolvation/solvation process. Thus, this much higher interfacial rate constant in aqueous electrolyte shall be attributed to the much larger pre-exponential factor of interface kinetic Arrhenius equation, because the desolvation process is much easier for Li-ions jumping from aqueous electrolyte to the Janus solid-liquid interface of LiFePO4.