Artificial Single-Ion Conducting Polymer Solid Electrolyte Interphase Layer toward Highly Stable Lithium Anode

Lithium (Li) as one of the most promising anode materials for the next-generation batteries was unfortunately plagued by the inevitable Li dendrite growth and the dynamically destroy/reconstruction of the unstable native solid electrolyte interphase (SEI) layer, which can severely affect the specific capacity and lifespan of lithium batteries, limiting the practical application of the Li anode. In this work, we designed a single ion conducting artificial polymer SEI layer on the surface of the Li anode. The fabricated SEI layer shows high ionic conductivity and lithium transference number, which is beneficial for inducing homogeneous Li deposition, effectively suppressing the nucleation and growth of dendrite. Moreover, the uniform and stable SEI layer with a well-designed network structure can availably protect the Li anode from directly contacting with the electrolyte, reducing the related side reactions and effectually limit the additional consumption of the active Li and electrolyte. The symmetric Li cells can cycle stably over 1200 h without short-circuit at the current/capacity densities of 1 (1 mAh/cm2) and 5 mA/cm2 (5 mAh/cm2). The assembled LiFePO4/LPEDV-Li cells exhibit high capacity retention up to 81.3% after 2400 cycles at the high rate of 8 C. Therefore, the designed artificial SEI layer with excellent properties presents a high application potential in stabilizing the Li anode.