Origin of Degradation in Si-Based All-Solid-State Li-Ion Microbatteries
Origin of Degradation in Si-Based All-Solid-State Li-Ion Microbatteries
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DOI：
10.1002/aenm.201801430
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发表时间：
2018-10-25
影响因子：
27.8
通讯作者：
Notten, Peter H. L.
中科院分区：
文献类型：
--
作者：
Chen, Chunguang;Oudenhoven, Jos F. M.;Notten, Peter H. L.
像所有的可充电电池系统一样，传统的锂离子电池(LiB)在运行过程中不可避免地会出现容量损失。这也适用于全固态LIB。在这项贡献中，发展了一种运行中中子深度剖面方法来研究全固态薄膜Si-Li_3PO_4-LiCoO_2电池的退化机理。阐明了长期降解机制的重要方面。研究发现，这些薄膜电池的容量损失主要与锂在固态电解液中的固定有关，在初始充电时，锂在负极/电解液界面开始增长。电解液中的锂固定层是由硅从阳极渗透到固态电解液中诱导的，并在随后的循环中以较低的速度继续增长。X射线光电子能谱深度剖析和透射电子显微镜分析证实了这种固定化层的形成，这有利于锂离子的离子导体。由于固定化过程，可自由移动的锂离子的数量减少，导致显著的存储容量衰减。从这项研究中获得的见解揭示了薄膜、全固态LiB的降解机理，并促进了潜在的界面修饰，最终将导致电池性能的显著改善。
Like all rechargeable battery systems, conventional Li-ion batteries (LIB) inevitably suffer from capacity losses during operation. This also holds for all-solid-state LIB. In this contribution an in operando neutron depth profiling method is developed to investigate the degradation mechanism of all-solid-state, thin film Si-Li3PO4-LiCoO2 batteries. Important aspects of the long-term degradation mechanisms are elucidated. It is found that the capacity losses in these thin film batteries are mainly related to lithium immobilization in the solid-state electrolyte, starting to grow at the anode/electrolyte interface during initial charging. The Li-immobilization layer in the electrolyte is induced by silicon penetration from the anode into the solid-state electrolyte and continues to grow at a lower rate during subsequent cycling. X-ray photoelectron spectroscopy depth profiling and transmission electron microscopy analyses confirm the formation of such immobilization layer, which favorably functions as an ionic conductor for lithium ions. As a result of the immobilization process, the amount of free moveable lithium ions is reduced, leading to the pronounced storage capacity decay. Insights gained from this research shed interesting light on the degradation mechanisms of thin film, all-solid-state LIB and facilitate potential interfacial modifications which finally will lead to substantially improved battery performance.