Lithium-Ion-Transfer Kinetics of Single LiFePO4 Particles

The Li-ion desertion process of a single LiFePO4 particle with a diameter of 400 nm in aqueous media at high potential is investigated by stochastic collision of the particle at a microelectrode. No extra additive, such as polymeric binder or conductive carbon, is involved in this stochastic measurement. The ion diffusion inside the particle is proved to be the rate determining step that limits the discharge rate of batteries using LiFePO4 in an aqueous environment. This result offers guidance for exploring the most effective enhancement of Li-ion batteries. Moreover, this general method can be applied to study the electrochemical behavior of other electrode materials as an alternative and complementary route.