Sodiophilic V 2 O 3 -Inducing Layer for Long Lifespan and Dendrite-Free Sodium Metal Anodes

Because of the superiority of low cost and high theoretical capacity, sodium metal batteries are considered an attractive option for high energy storage. However, the uncontrollable and random deposition of Na tends to expedite the formation of Na dendrites and increases the risk of thermal runaway. The method of preplant sodiophilic sites can induce the lateral deposition of Na instead of sharp dendrite emergence. Here, we introduce the sodiophilic V 2 O 3 particles to form a protective layer on Na surface (Na/V 2 O 3 ). The high Na ion adsorption energy and low nucleation overpotential of Na/V 2 O 3 facilitate the diffusion of Na ions and homogeneous Na deposition, which can work well in cubing dendrite development. Thus, the symmetrical cell (Na/V 2 O 3 ||Na/V 2 O 3 ) can stably operate for 670 h at 0.5 mA·cm −2 /1 mAh·cm −2 with a smaller voltage hysteresis (less than 100 mV). Moreover, full cell constructed by coupling Na/V 2 O 3 anode with Na 3 V 2 (PO 4 ) 3 cathode displays an outstanding rate performance, maintaining a high capacity of 70 mAh·g −1 at 30 C. On the basis of the design of sodiophilic protection layer, a dendrite-free, outstanding rate performance, and long lifespan sodium metal battery is realized.