Molecular Engineering on Solvation Structure of Carbonate Electrolyte toward Durable Sodium Metal Battery at −40 °C

Abstract

Carbonate electrolytes have excellent chemical stability and high salt solubility, which are ideally practical choice for achieving high‐energy‐density sodium (Na) metal battery at room temperature. However, their application at ultra‐low temperature (−40 °C) is adversely affected by the instability of solid electrolyte interphase (SEI) formed by electrolyte decomposition and the difficulty of desolvation. Here, we designed a novel low‐temperature carbonate electrolyte by molecular engineering on solvation structure. The calculations and experimental results demonstrate that ethylene sulfate (ES) reduces the sodium ion desolvation energy and promotes the forming of more inorganic substances on the Na surface, which promote ion migration and inhibit dendrite growth. At −40 °C, the Na||Na symmetric battery exhibits a stable cycle of 1500 hours, and the Na||Na3V2(PO4)3 (NVP) battery achieves 88.2 % capacity retention after 200 cycles.

Status and strategies of electrolyte engineering for low-temperature sodium-ion batteries

“…Yu et al used ES to reduce the de-solvation energy of Na + , promoting the migration of ions and inhibiting dendrite growth. 126 The Na‖Na symmetrical battery could maintain a stable cycle for 1500 hours at −40 °C. The Na‖NVP batteries could also maintain a high capacity of 88.2% after 200 cycles.…”

In situ formed self-embedded ion/electron conductive skeletons enabling highly stable sodium metal anodes

“…9,16 The continuous reconstruction of the SEI film can expedite the consumption of active Na and the electrolyte, leading to a low coulombic efficiency (CE) and shortened cycling lifespan. 15,17 Up to now, considerable efforts have been devoted to resolving the aforementioned problems, mainly including the construction of three-dimensional (3D) skeletons for relieving the volume expansion upon cycling, 13,18,19 optimizing electrolyte components for improving the interfacial stability between the electrode and electrolyte, [20][21][22][23] and engineering an artificial SEI layer for homogenizing the Na + flux near the electrode. 5,24,25 Among them, the construction of a 3D skeleton can fundamentally improve the electrochemical performance and safety of SMAs by minimizing the local current density and alleviating the volume change during cycling.…”

The introduction of gallium ions into V2O5 interlayers for highly reversible Zn ion batteries

“…It is necessary to design and develop many sustainable energy sources. [1][2][3][4] Among them, Li-ion batteries (LIBs) have been utilized in smartphones, electric vehicles and laptops. Nevertheless, their future development is still restricted considering the high cost and toxic organic electrolyte.…”