State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment , Tsinghua University , Beijing 100084 , China.
Environ Sci Technol. 2018 Nov 20;52(22):13136-13143. doi: 10.1021/acs.est.8b03469. Epub 2018 Nov 12.
This research presented the impacts of mechanochemical activation (MCA) on the physiochemical properties of lithium cobalt oxide (LiCoO) powders of cathode materials from spent lithium-ion batteries, and analyzed the relevant effects of these changes on the leaching efficiency of lithium and cobalt and the leaching kinetics of LiCoO powders. The results revealed the superiority of MCA in the following levels of changes in the LiCoO powders: first, the physical properties included a decrease in the average particle size, an increase in the specific surface area, and the appearance of a mesoporous structure change; second, changes in crystal-phase structures were reflected in the grain refinement of LiCoO powders, lattice distortions, lattice dislocations, and storage and increment of internal energy; third, the surface characteristics included a chemical shift of lithium element electrons, a reduction in Co concentration, and an increment in the surface hydroxyl oxygen concentration. These changes in physiochemical properties and structures enhanced the hydrophilicity and interface reactivity of the activated LiCoO powders and significantly improved the leaching efficiencies of Li and Co in organic acid solutions. The rate-limiting step of metal leaching was also altered from a surface chemical reaction-controlled one before MCA to an ash layer diffusion-controlled one after MCA.
本研究介绍了机械化学活化（MCA）对废旧锂离子电池正极材料钴酸锂（LiCoO）粉末的物理化学性质的影响，并分析了这些变化对锂和钴浸出效率以及 LiCoO 粉末浸出动力学的相关影响。结果表明，MCA 在以下几个方面对 LiCoO 粉末具有优越性：首先，物理性质包括平均粒径减小、比表面积增大和出现中孔结构变化；其次，晶体相结构的变化体现在 LiCoO 粉末的晶粒细化、晶格畸变、位错以及内部能量的储存和增加；第三，表面特性包括锂元素电子的化学位移、Co 浓度降低以及表面羟基氧浓度增加。这些物理化学性质和结构的变化增强了活化 LiCoO 粉末的亲水性和界面反应性，显著提高了 Li 和 Co 在有机酸溶液中的浸出效率。浸出过程的速率限制步骤也从 MCA 之前的表面化学反应控制转变为 MCA 之后的灰分层扩散控制。
