Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
Nano Lett. 2011 Nov 9;11(11):4890-6. doi: 10.1021/nl202764f. Epub 2011 Oct 20.
Using a novel electrochemical phase-field model, we question the common belief that Li(X)FePO(4) nanoparticles always separate into Li-rich and Li-poor phases during battery discharge. For small currents, spinodal decomposition or nucleation leads to moving phase boundaries. Above a critical current density (in the Tafel regime), the spinodal disappears, and particles fill homogeneously, which may explain the superior rate capability and long cycle life of nano-LiFePO(4) cathodes.
利用新颖的电化学相场模型，我们对普遍存在的观点提出质疑，即在电池放电过程中，Li(X)FePO(4)纳米颗粒总是会分离成富锂相和贫锂相。对于小电流，旋节分解或成核导致移动的相界。在临界电流密度以上（塔菲尔区），旋节消失，颗粒均匀填充，这可能解释了纳米 LiFePO(4)正极具有优异的倍率性能和长循环寿命的原因。
