Choi Yong Seok, Lee Young-Su, Oh Kyu Hwan, Cho Young Whan
High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea.
Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Republic of Korea.
Phys Chem Chem Phys. 2016 Aug 10;18(32):22540-7. doi: 10.1039/c6cp03563a.
We have developed a fast solid state Li ion conductor composed of LiBH4 and SiO2 by means of interface engineering. A composite of LiBH4-SiO2 was simply synthesized by high energy ball-milling, and two types of SiO2 (MCM-41 and fumed silica) having different specific surface areas were used to evaluate the effect of the LiBH4/SiO2 interface on the ionic conductivity enhancement. The ionic conductivity of the ball-milled LiBH4-MCM-41 and LiBH4-fumed silica mixture is as high as 10(-5) S cm(-1) and 10(-4) S cm(-1) at room temperature, respectively. In particular, the conductivity of the latter is comparable to the LiBH4 melt-infiltrated into MCM-41. The conductivities of the LiBH4-fumed silica mixtures at different mixing ratios were analyzed employing a continuum percolation model, and the conductivity of the LiBH4/SiO2 interface layer is estimated to be 10(5) times higher than that of pure bulk LiBH4. The result highlights the importance of the interface and indicates that significant enhancement in ionic conductivity can be achieved via interface engineering.
我们通过界面工程开发了一种由LiBH₄和SiO₂组成的快速固态锂离子导体。LiBH₄-SiO₂复合材料通过高能球磨简单合成，使用两种具有不同比表面积的SiO₂（MCM-41和气相二氧化硅）来评估LiBH₄/SiO₂界面在提高离子电导率方面的作用。球磨后的LiBH₄-MCM-41和LiBH₄-气相二氧化硅混合物在室温下的离子电导率分别高达10⁻⁵ S cm⁻¹和10⁻⁴ S cm⁻¹。特别是，后者的电导率与熔渗到MCM-41中的LiBH₄相当。采用连续渗流模型分析了不同混合比例的LiBH₄-气相二氧化硅混合物的电导率，估计LiBH₄/SiO₂界面层的电导率比纯块状LiBH₄高10⁵倍。该结果突出了界面的重要性，并表明通过界面工程可以显著提高离子电导率。
