水溶液法原位构建ZnO亲锂层稳定锂-石榴石电解质界面  

In situ Lithiophilic ZnO Layer Constructed using Aqueous Strategy for a Stable Li-Garnet Interface

作　　者：蔡明俐 姚柳 靳俊[1,2] 温兆银 Mingli Cai;Liu Yao;Jun Jin;Zhaoyin Wen(CAS Key Laboratory of Materials for Energy Conversion,Shanghai Institute of Ceramics,Chinese Academy of Sciences,Shanghai 200050,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China.)

机构地区：[1]中国科学院上海硅酸盐研究所,能量转换材料重点实验室,上海200050 [2]中国科学院大学材料与光电研究中心,北京100049

出　　处：《物理化学学报》2021年第1期6-12,共7页Acta Physico-Chimica Sinica

基　　金：国家重点研发项目(2018YFB0905400);国家自然科学基金项目(51772315);上海市科学技术委员会项目(18DZ2280800)资助。

摘　　要：固态电池以其高安全性和高能量密度而备受关注。石榴石型固体电解质(LLZO)由于具有较高的离子导电性和对锂金属的稳定性,在固态电池中具有应用前景,但陶瓷与锂金属较差的界面接触会导致高的界面阻抗和可能形成的枝晶穿透。我们利用LLZO表层独特的H^(+)/Li^(+)交换反应,提出了一种简便有效的金属盐类水溶液诱发策略,在电解质表面原位构建ZnO亲锂层,界面处LiZn合金化实现紧密连续的接触。引入改性层后,界面阻抗可显著降低至约10Ω·cm^(2),对称电池能够在0.1mA·cm^(-2)的电流密度下实现长达1000h的长循环稳定性。匹配正极LiFePO_(4)(LFP)或LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(NCM523)的准固态电池在室温下能够稳定循环100次以上。Solid-state batteries have garnered significant attention,owing to their high safety and improved energy density.Among various solid-state electrolytes (SSEs),garnet-type SSEs are promising for application in solid-state batteries,owing to their high ionic conductivities (10^(-4)–10^(-3) S·cm^(-1)) at room temperature and excellent stability against Li metal.However,the poor contact between the rigid ceramic and Li metal will result in high interfacial impedance and uneven lithium ion flux during cycling.Consequently,this will lead to rapid dendrite penetration along the grain boundary and eventual short circuit.Herein,inspired by the unique H^(+)/Li^(+) exchange reaction of the garnet electrolyte,we propose a facile and efficient metal salt aqueous-solution-based strategy to construct an in situ lithiophilic Zn O layer on the garnet surface without employing any specific apparatus.A Zn(NO_(3))_(2) aqueous solution was selected to modify the garnet surface.Within one minute,Li OH spontaneously formed as a result of the H^(+)/Li^(+) exchange reaction reacted with Zn(NO_(3))_(2) to produce homogeneous precipitates.After heat treatment,a lithiophilic Zn O layer was obtained.This was verified by the results of X-ray diffraction and attenuated total reflection Fourier transform infrared spectroscopy analyses.Furthermore,combined with scanning electron microscopy(SEM) images and corresponding elemental mapping,it was proved that a thin in situ interlayer can be successfully deposited on the garnet surface using our strategy.Moreover,the deposited Zn O nanoparticles were uniformly and densely distributed on the garnet surface.In the presence of the introduced layer,the wettability of the garnet-type SSE with molten Li was greatly improved.The introduced Zn O nanoparticles reacted with molten Li to form a Li Zn alloy,achieving a tight and continuous contact at the Li–garnet interface,thereby greatly reducing the interfacial impedance to~10Ω·cm^(2).In the case of the untreated SSE in contact with the molten Li,the

关 键 词：石榴石电解质 Zn(NO3)2水溶液 原位修饰 界面稳定性 固态锂电池 

分 类 号：O646[理学—物理化学]