Interfacial nucleation mechanisms in reservoir-free Na all solid-state batteries using ultrathin interlayers and low stack pressure
File(s)
Author(s)
Type
Journal Article
Abstract
Controlling sodium nucleation at the current collector|solid electrolyte interface remains a key challenge for realizing “reservoir-free” sodium all-solid-state batteries (RF-ASSBs), particularly under low stack pressure. While metals have been explored as sodium hosts or current collectors, the use of ultrathin metallic interlayers capable of regulating sodium nucleation with minimal sodium inventory penalty remains largely unexplored. Here, we present a comparative interfacial study of 50 nm sputtered Sn and In interlayers deposited on NaSICON electrolytes. By combining electrochemical characterization, microelectrode experiments, and operando and ex situ time-of-flight secondary ion mass spectrometry, we directly probe early-stage sodium nucleation, interfacial chemistry, and reversibility. Sn undergoes electrochemically driven Na–Sn alloy formation independent of current rate and with high sodium diffusivity, enabling homogeneous nucleation and stable plating/stripping through a persistent alloy interphase while incurring only minimal irreversible sodium loss (∼0.031 mAh cm−2). In contrast, In fails to sustain stable interfacial sodium transport, leading to subfilm sodium deposition, mechanical disruption of the interlayer, sodium trapping, and rapid interfacial failure. These results demonstrate that, for ultrathin interlayers operated under low stack pressure, alloy-assisted fast sodium transport within a stabilized interlayer, rather than generic sodiophilicity, governs interfacial stability, providing mechanistic design guidelines for RF-ASSBs.
Date Issued
2026-05-19
Date Acceptance
2026-04-30
Citation
ChemElectroChem, 2026, 13 (10)
ISSN
2196-0216
Publisher
Wiley
Journal / Book Title
ChemElectroChem
Volume
13
Issue
10
Copyright Statement
© 2026 The Author(s). ChemElectroChem published by Wiley-VCH GmbH This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
License URL
Identifier
10.1002/celc.70231
Subjects
alloy
chemical engineering
current collector
electrolyte
interfacial stability
materials science
nucleation
plating
secondary ion mass spectrometry
sodium
Publication Status
Published
Article Number
e70231
Date Publish Online
2026-05-18