原子力显微镜特别适合作为锂离子电池研究的工具,以应对改善电池容量,功率密度,寿命和安全性的关键挑战。从根本上讲,电池是电化学电池,电化学AFM可以用于直接,原位和操作中电极表面的变化,甚至测量局部电化学活性的变化。例如,对高容量液体阳极的AFM研究可以帮助了解固体 - 电解质相间层(SEI)层的演化和降解,这限制了功率密度和电池寿命。在阴极,相关的电和机械表征可以量化组件分布,表征电导率变化,并确定限制容量的非活性金属氧化物晶粒。最后,在拉伸阶段对分离膜的AFM成像可以提供对破裂机制的洞察力,当树突生长导致灾难性衰竭时。
在存在电解质的情况下,测量局部电化学活性和表面电导率的能力对于表征其他能源存储和转换方法(例如超级电容器,燃料电池和太阳能燃料)同样有用。
锂离子电池的寿命取决于致命一击ically on the formation and evolution of the passivating SEI layer. The challenge lies in the large electrode volume changes during battery cycling, which leads to substantial deformation of the SEI layer, especially for high capacity anodes. The ideal experiment would probe the fragile SEI layer directly, in operando, a feat that used to be considered very difficult. The series of images shown here does just that and is from collaborative work performed with the Sheldon group at Brown University. Here patterned Si anodes were observed using PeakForce QNM, in a glove box integrated尺寸图标®带有电化学细胞。在静脉内,首次直接观察到SEI层中裂纹的形成。在多个充电循环中,正在跟踪机械降解,这些循环显示不完全修复初始裂纹,这与先前的猜测相矛盾。
这些实验还为估计断裂韧性的大门是SEI层崩溃的关键参数(请参阅我们合着的ACS Energy Letters文章,“原位和操作研究对硅电极上固体电解质之间的故障机理的研究”). For further studies on the SEI layer, see also the recent Nature Communications article, “锂阳极在空气中稳定,用于低成本制造无树突的锂电池,” coauthored by Nobel Laureate John Goodenough.
Lithium ion cathodes are a complex and heterogeneous mix containing metal oxide particles to store the Lithium in the discharged state, surrounded by polymeric binder material that accommodates volume changes mixed with carbon black material to maintain high conductivity and thus ability to deliver high power density. The image series here shows how DataCube SSRM on a尺寸图标XR有助于绘制成分分布,并将巨大的粒子弄清到粒子变化。在这里,DataCube模式下可用的模量图清楚地将硬金属氧化物颗粒与周围的软粘合剂区分开,而同时获得的电导率图揭示了碳黑色的不均匀分布。图像的顶部边缘附近的粒子不被碳黑色覆盖,并且从相同数据立方体提取的一系列电导率图像将该粒子识别为死亡,即在整个工作电压范围内无效。
Read our Battery Research e-book, which introduces the main analytical techniques used to characterize Li-ion battery materials, including atomic force microscopy (AFM) characterization. The e-book explains how these techniques and their various modes work, and details how they are used for analyzing battery materials and what kind of information they can produce. It also presents case studies to illustrate how the techniques are being applied by working scientists in the laboratory.