Understanding and Comparing the Stability of Water‐ versus NMP‐Based Tin(IV)Sulfide Electrodes Using Post‐Mortem Analysis

Abstract Tin (IV) sulfide (SnS 2 ) is a promising anode material for Li‐ion batteries (LIBs) due to its high practical reversible capacity of 623 mAhg −1 . However, its cycling stability is relatively poor and its long‐term degradation during cycling is not yet thoroughly investigated. In this work, a post‐mortem analysis of SnS 2 electrodes was performed at pristine state, after the 1 st cycle and at 80 % state‐of‐health. The analysis compared water‐based (Na‐CMC/SBR) and NMP‐based (PVDF) electrodes revealing insights into their degradation mechanisms and electrochemical performance. During the first cycle, SnS 2 converts into Sn and Li 2 S identified by XRD, causing particle cracking and exfoliation. XPS and Raman spectroscopy identified Sn, SnF x , LiF, Li 2 S and carbonates species forming the solid electrolyte interphase (SEI), while in‐situ dilatometry revealed up to 60 % irreversible expansion after the first cycle. These species are also found after at 80 % SOH along with an increase in fluorine species, SEI thickness and interfacial resistance. Water‐based electrodes exhibited better cycling stability, with 80 wt.% SnS 2 and 10 wt.% binder retaining 80 % capacity after 180+ cycles. These findings underscore the critical role of binder choice and processing in enhancing SnS 2 anodes’ durability and capacity retention, paving the way for sustainable, high‐performance LIB anodes.