Large volume modifications during electrochemical cycling of electrodes in Li-ion batteries often limit successful applications due to stress formation, electrode fracture and delamination from the current collector. In this study, we carried out investigations on the volume changes taking place during potentiostatic lithiation of the high capacity electrode material amorphous silicon. Thin film electrodes were investigated at potentials of 0.45, 0.28, 0.19 und 0.06 V vs Li/Li⁺ during lithiation using in-operando neutron reflectometry. We found a strongly non-linear correlation between volume and state-of-charge for each potential applied in strong contrast to the results of galvanostatic lithiation. A possible explanation might be that for high current densities occurring at the beginning of each potentiostatic lithiation step free volumes are created in the electrode material leading to disproportionate volume expansion.

由于应力形成，电极断裂和集电器的分层，锂离子电池中电极的电化学循环过程中的大体积修改通常会限制成功的应用。在这项研究中，我们对高容量电极材料非晶硅的恒电位锂化过程中发生的体积变化进行了研究。与Li / Li ^+相比，在0.45、0.28、0.19和0.06 V的电势下研究薄膜电极使用操作中中子反射计在锂化过程中。我们发现，与恒电流锂化的结果形成鲜明对比的是，每种电势在体积和荷电状态之间都存在强烈的非线性关系。一个可能的解释可能是，对于在每个恒电位锂化步骤开始时出现的高电流密度，在电极材料中会产生自由体积，从而导致不成比例的体积膨胀。