The lithium intercalation into ion-beam sputter-deposited films of lithium manganese oxide is studied as a function of the film thickness (50–500 nm). The kinetics of the intercalation is quantified in cyclic voltammetry under variation of the scanning rate over five orders of magnitude (0.005–768 mV/s). With an increasing rate, the intercalation currents reveal a transition from a finite length diffusion to a semi-infinite diffusion behavior, as it is expected from continuum transport equations. But surprisingly, the peak current in the Randles-Sevcik regime scales with the square root of film thickness. Consequently, the diffusion coefficient apparently increases with the layer thickness. Combining the parameters of the actual microstructure of the thin films with an appropriate kinetic modeling that includes the effects of grain boundaries, it is shown that the observed acceleration is quantitatively understood by outstandingly fast short-circuit transport in a type B kinetic regime of grain boundary diffusion.

研究了锂嵌入锰酸锂离子束溅射沉积膜中随膜厚（50-500 nm）的变化。在扫描速度变化超过五个数量级（0.005-768 mV / s）的情况下，在循环伏安法中定量了插层动力学。随着速率的增加，插入电流显示出从有限长度扩散到半无限扩散行为的转变，这是从连续输运方程式预期的。但令人惊讶的是，Randles-Sevcik体制中的峰值电流与薄膜厚度的平方根成比例。因此，扩散系数显然随层厚度而增加。将薄膜的实际微观结构参数与适当的动力学模型（包括晶界的影响）结合起来，