Toyota Central Research & Development Laboratories, Inc. , 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan.
ACS Appl Mater Interfaces. 2017 Jan 18;9(2):1507-1515. doi: 10.1021/acsami.6b13224. Epub 2017 Jan 5.
Although all-solid-state lithium-ion batteries (ALIBs) have been believed as the ultimate safe battery, their true character has been an enigma so far. In this paper, we developed an all-inclusive-microcell (AIM) for differential scanning calorimetry (DSC) analysis to clarify the degree of safety (DOS) of ALIBs. Here AIM possesses all the battery components to work as a battery by itself, and DOS is determined by the total heat generation ratio (ΔH) of ALIB compared with the conventional LIB. When DOS = 100%, the safety of ALIB is exactly the same as that of LIB; when DOS = 0%, ALIB reaches the ultimate safety. We investigated two types of LIB-AIM and three types of ALIB-AIM. Surprisingly, all the ALIBs exhibit one or two exothermic peaks above 250 °C with 20-30% of DOS. The exothermic peak is attributed to the reaction between the released oxygen from the positive electrode and the Li metal in the negative electrode. Hence, ALIBs are found to be flammable as in the case of LIBs. We also attempted to improve the safety of ALIBs and succeeded in decreasing the DOS down to ∼16% by incorporating Ketjenblack into the positive electrode as an oxygen scavenger. Based on ΔH as a function of voltage window, a safety map for LIBs and ALIBs is proposed.
尽管全固态锂离子电池（ALIBs）被认为是终极安全电池，但迄今为止，其真正性质仍不为人知。在本文中，我们开发了一种用于差示扫描量热法（DSC）分析的综合微电池（AIM），以阐明 ALIB 的安全程度（DOS）。在这里，AIM 拥有所有电池组件，可以自行作为电池工作，DOS 由 ALIB 与传统 LIB 的总发热率（ΔH）决定。当 DOS = 100%时，ALIB 的安全性与 LIB 完全相同；当 DOS = 0%时，ALIB 达到了终极安全。我们研究了两种 LIB-AIM 和三种 ALIB-AIM。令人惊讶的是，所有的 ALIB 在 250°C 以上都显示出一个或两个放热峰，DOS 在 20-30%之间。放热峰归因于正极释放的氧气与负极锂金属之间的反应。因此，ALIB 被发现像 LIB 一样易燃。我们还试图提高 ALIB 的安全性，并成功地通过在正极中加入 Ketjenblack 作为氧气清除剂将 DOS 降低到约 16%。基于 ΔH 作为电压窗口的函数，提出了 LIB 和 ALIB 的安全图。
