Chen Linhui, Zhang Jian, Tong Rong-Ao, Zhang Jingxi, Wang Hailong, Shao Gang, Wang Chang-An
State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
School of Materials Science and Engineering, Zhengzhou University, Zhengzhou, Henan, 450001, China.
Small. 2022 Feb;18(8):e2106142. doi: 10.1002/smll.202106142. Epub 2021 Dec 11.
Garnet-type Li La Zr Ta O (LLZTO) electrolyte is considered as a promising solid electrolyte because of its relatively high ionic conductivity and excellent electrochemical stability. The surface contamination layer and poor Li/LLZTO interface contact cause large interfacial resistance and quick Li dendrite growth. In this paper, a porous hard carbon layer is introduced by the carbonization of a mixed layer of phenolic resin and polyvinyl butyral on the LLZTO surface to improve Li/garnet interfacial wettability. The multi-level pore structure of the hard carbon interlayer provides capillary force and large specific surface area, which, together with the chemical activity of the carbon material with Li, promote the molten Li infiltration with garnet electrolyte. The Li/LLZTO interface delivers a low interfacial resistance of 4.7 Ω∙cm at 40 °C and a higher critical current density, which can achieve stable Li conduction for over 800 h under current densities of 0.1 and 0.2 mA∙cm . The solid-state battery coupled with Li and LiFePO exhibits excellent rate and cycling performance, demonstrating the application feasibility of the hard carbon interlayer for a solid state Li metal battery.
石榴石型Li La Zr Ta O（LLZTO）电解质因其相对较高的离子电导率和优异的电化学稳定性而被认为是一种很有前途的固体电解质。表面污染层和较差的Li/LLZTO界面接触会导致较大的界面电阻和锂枝晶快速生长。本文通过在LLZTO表面碳化酚醛树脂和聚乙烯醇缩丁醛的混合层引入多孔硬碳层，以改善Li/石榴石界面润湿性。硬碳中间层的多级孔结构提供了毛细作用力和大比表面积，再加上碳材料与锂的化学活性，促进了熔融锂与石榴石电解质的浸润。Li/LLZTO界面在40℃时具有4.7Ω∙cm的低界面电阻和更高的临界电流密度，在0.1和0.2 mA∙cm的电流密度下可实现超过800小时的稳定锂传导。与锂和磷酸铁锂耦合的固态电池表现出优异的倍率和循环性能，证明了硬碳中间层在固态锂金属电池中的应用可行性。
