Rational design of artificial interphase buffer layer with 3D porous channel for uniform deposition in magnesium metal anodes

Abstract

Rechargeable magnesium (Mg) metal batteries (RMBs) have received extensive attention due to their high theoretical capacity and superior safety. However, the heterogeneous plating/stripping behavior and detrimental corrosion issues of Mg metal hinder the practical application of RMBs. The failure of the Mg metal anode when cycling under high areal capacity utilization is of rising concern. Herein, we have developed a facile and effective approach to realize stable Mg metal anode with artificial solid-electrolyte interphase (SEI) layers by in-situ dynamic self-assembly coordination of phytic acid (PA) with Mg2+. Especially, the 3D porous channel structure of interfacial PA skeleton could regulate ion flux via coordination, efficiently homogenizing the distribution of Mg2+ and successfully triggers uniform plating/stripping Mg by experimental results and theoretical calculation. Encouragingly, the symmetric cells using as-prepared Mg metal anode possess low voltage hysteresis (250 mV) and long cycle life (780 cycles) under harsh utilization condition (3 mA cm−2, 1 mAh cm−2). The effectiveness of 3D porous channel buffer artificial SEI is further demonstrated in the Mg-Mo6S8 full cells. Such an advanced strategy for modulating Mg2+ transport provides an avenue to addressing the basic challenges for RMBs, which can potentially be extended to other construction of highly tolerant and conductive artificial SEI layers.