The general lithium hydroxide monohydrate (LiOH·H₂O) recovery method from waste cathode materials has environmental problems due to the use of strong acids and economic problems associated with the process of converting to LiOH·H₂O. In this study, surprisingly, LiOH·H₂O was successfully recovered from the LiNi_0.92Co_0.07Al_0.11O₂ cathode materials through a novel vacuum heat-treatment method. Due to the low oxygen partial pressure (2.7 × 10^–7 atm), the phase transition from a conventional layered structure to a RS (rock salt) structure occurred at 700 ℃. The results from the X-ray diffraction (XRD) analysis confirmed that the (003) peak, which indicates the amount of lithium in the cathode structure, completely disappeared at temperature of 800 °C and above. After vacuum heat treatment, the obtained aqueous solution was evaporated and concentrated to obtain a crystallized white powder. As a result of the XRD analysis of this product, LiOH·H₂O was indexed. To our knowledge, this is a novel method of LiOH·H₂O recovery from nickel-rich cathode materials.

由于使用强酸，从废正极材料中回收一水氢氧化锂 (LiOH·H ₂ O)的一般方法存在环境问题以及与转化为 LiOH·H ₂ O的过程相关的经济问题。在这项研究中，令人惊讶的是，采用新型真空热处理方法从LiNi _0.92 Co _0.07 Al _0.11 O ₂正极材料中成功回收LiOH·H ₂ O。由于氧分压低 (2.7 × 10 ^–7 atm)，从常规层状结构到 RS（岩盐）结构的相变发生在 700 ℃。X 射线衍射 (XRD) 分析的结果证实，表示阴极结构中锂含量的 (003) 峰在 800°C 及以上的温度下完全消失。真空热处理后，将得到的水溶液蒸发浓缩，得到白色结晶粉末。作为该产物的XRD分析的结果，LiOH·H ₂ O被标定。据我们所知，这是一种从富镍正极材料中回收LiOH·H ₂ O的新方法。