Abstract：
The low ionic and electronic conductivity between current solid electrolytes and high-capacity anodes limits the long-term cycling performance of all-solid-state lithium-ion batteries (ASSLIBs). Herein, this work reports the fabrication of an ultra-stable electrode-solid electrolyte composite for high-performance ASSLIBs enabled by the homogeneous coverage of ultrathin Mg(BH4 )2 layers on the surface of each MgH2 nanoparticle that are uniformly distributed on graphene. The initial discharge process of Mg(BH4 )2 layers results in uniform coverage of MgH2 nanoparticle with both LiBH4 as the solid electrolyte and Li2 B6 with even higher Li ion conductivity than LiBH4 . Consequently, the Li ion conductivity of graphene-supported MgH2 nanoparticles covered with ultrathin Mg(BH4 )2 layers is two orders of magnitude higher than that without Mg(BH4 )2 layers. Moreover, the thus-formed inactive Li2 B6 with strong adsorption capability toward LiBH4 , acts as a stabilizing framework, which, coupled with the structural support role of graphene, alleviates the volume change of MgH2 nanoparticles and facilitates the intimate contact between LiBH4 and individual MgH2 nanoparticles, leading to the formation of uniform stable interfaces with high ionic and electronic conductivity on each MgH2 nanoparticles. Hence, an ultrahigh specific capacity of 800 mAh g-1 is achieved for MgH2 at 2 A g-1 after 350 cycles.
摘要：
当前固体电解质和高容量阳极之间的低离子和电子电导率限制了全固态锂离子电池（ASSLIB）的长期循环性能。在这里，这项工作报告了用于高性能ASSLIB的超稳定电极-固体电解质复合材料的制造，该复合材料通过在每个均匀分布在石墨烯上的MgH2纳米颗粒的表面上均匀覆盖超薄Mg（BH4）2层而实现。Mg（BH4）2层的初始放电过程导致MgH2纳米颗粒的均匀覆盖，其中LiBH4作为固体电解质，Li2B6具有比LiBH4更高的Li离子电导率。因此,覆盖有超薄Mg(BH4)2层的石墨烯负载的MgH2纳米颗粒的Li离子电导率比没有Mg(BH4)2层的Li离子电导率高两个数量级。此外，由此形成的对LiBH4具有强吸附能力的惰性Li2B6，作为一个稳定的框架，which,再加上石墨烯的结构支撑作用，减轻MgH2纳米颗粒的体积变化，促进LiBH4和单个MgH2纳米颗粒之间的密切接触，导致在每个MgH2纳米颗粒上形成具有高离子和电子电导率的均匀稳定界面。因此，在350次循环后，MgH2在2Ag-1下实现了800mAhg-1的超高比容量。
