Sodium (Na) metal is a promising alternative to lithium metal as an anode material for the next-generation energy storage devices due to its high theoretical capacity, low cost, and natural abundance. However, dendritic/mossy Na growth caused by uncontrollable plating/stripping results in serious safe concerns and rapid electrode degradation. This study presents Sn2+ pillaredTi3C2 MXene serving as a stable matrix for high-performance dendrite-free Na metal anode. The intercalated Sn2+ between Ti3C2 layers not only induces Na to nucleate and grow within Ti3C2 interlayers, but also endows the Ti3C2 with larger interlayer space to accommodate the deposited Na by taking advantage of the “pillar effect” that leads to uniform Na deposition. As a result, the pillar-structured MXene-based Na metal anode enables high current density (up to 10 mA cm-2) along with high areal capacity (up to 5 mAh cm-2) over long-term cycling (up to 500 cycles). The full cell using MXene-based Na metal anode exhibits superior electrochemical performance than that with host-less commercial Na. It is believed that the well-controlled MXene-based Na anode not only extends the application scope of MXene, but also provides guidance in designing high-performance and safe Na metal batteries.

Pillared MXene with ultralarge interlayer spacing as a stable matrix for high performance sodium metal anodes

2019 Fall National Meeting

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