设计和建造人工固体电解质界面膜实现锂金属阳极无枝晶形态

Design and Construction of Artificial Solid Electrolyte Interface Film for Dendrite-free Lithium Metal Anode

锂金属与电解质自发反应形成的固体电解质界面膜在成分和形态上的不均匀是诱导锂枝晶生长的重要因素,为了解决这个问题,本文设计和建造由聚偏二氟乙烯和Li7La3Zr2O12组成的人工固体电解质界面膜,该膜具有稳定的、均匀的成分和形态,可以为电极和电解液的固液界面建立均匀的电场,从而诱导锂均匀的成核和生长,无机纳米颗粒Li7La3Zr2O12具有良好的Li+传输性能,并且可以减缓聚偏二氟乙烯的结晶,稳定聚偏二氟乙烯的化学形态,聚偏二氟乙烯具有良好的机械性能,可以适应锂金属阳极在循环中体积的变化。利用该保护膜,在Li与LiNi0.5Co0.2Mn0.3O2(NCM523)组成的全电池在恒流测试中表现出稳定的放电容量保持率和库伦效率。

The heterogeneity of composition and morphology of the solid electrolyte interface film formed by the spontaneous reaction of lithium metal and electrolyte is an important factor inducing the growth of lithium dendrite.Here,an artificial solid electrolyte interface consisting of polyvinylidene difluoride and Li7La3Zr2O12 with homogeneous composition and morphology was designed and constructed.It can establish a uniform electric field for the solid-liquid interface inducing the uniform nucleation and growth of lithium.The inorganic Li7La3Zr2O12 nanoparticles have good Li+transport performance and can stabilize the chemical form of polyvinylidene difluoride by slowing down the crystallization of polyvinylidene difluoride,which has good mechanical properties and can adapt to the volume change of lithium metal anode during the cycle.Using the protective film,the full cell with lithium as anode and LiNi0.5Co0.2Mn0.3O2 as cathode shows a stable discharge capacity retention rate and coulomb efficiency in the constant current test.