Tungsten and Boron Codoping toward High Ionic Conductivity and Stable Sodium Solid Electrolyte for All-Solid-State Sodium Batteries

Abstract

Sodium solid electrolytes with high ionic conductivity and good interfacial stability with sodium metal are crucial to realize high-performance allsolid-state sodium batteries. In this work, W and B-codoped Na 3 Sb 1−x W x S 4−x B x solid electrolytes are prepared by melt-quenching with further annealing. The synthesized Na 3 Sb 0.95 W 0.05 S 3.95 B 0.05 solid electrolyte possesses a high ionic conductivity of 11.06 mS cm −1 under 25 °C and shows significantly improved interface compatibility with metal sodium. Specifically, Na/Na 3 Sb 0.95 W 0.05 S 3.95 B 0.05 / Na symmetric cell can stable cycle for 500 h under a current density of 0.05 mA cm −2 . In addition, the resultant TiS 2 /Na 3 Sb 0.95 W 0.05 S 3.95 B 0.05 /Na battery exhibits an initial charge capacity of 164.1 mAh g −1 at 0.1 C with a capacity retention of 76.4% after 100 cycles. This work provides a new strategy to realize the high ionic conductivity of sodium solid electrolytes with improved interfacial stability with sodium anode.

High-Strength, Thin, and Lightweight Solid Polymer Electrolyte for Superior All-Solid-State Sodium Metal Batteries

“…Owing to the scarcity and uneven geographical distribution of lithium resources (0.0017 wt % in the earth’s crust), sodium batteries based on abundant sodium resources (2.3 wt % in the earth’s crust) have gradually become potential supplements or alternatives to lithium batteries. , Besides this, benefiting from sodium’s high theoretical specific capacity of 1165 mAh g –1 and low reduction potentials (−2.71 V vs the standard hydrogen electrode), the battery can be further endowed with low cost and high energy density using Na metal as anode . However, traditional sodium metal batteries (SMBs) generally use highly flammable organic liquid electrolytes, which may lead to catastrophic battery accidents such as fire and explosions. − Furthermore, SMBs for practical applications are always hampered by the notorious dendrite growth that can penetrate the separator and cause battery short circuits . The most promising solution to these problems is using a solid-state electrolyte instead of a liquid electrolyte, which can offer greater safety. − …”