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Reversible Conversion Reactions and Small First Cycle Irreversible Capacity Loss in Metal Sulfide‐Based Electrodes Enabled by Solid Electrolytes
Author(s) -
Kim Sanghyeon,
Choi Jaewon,
Bak SeongMin,
Sang Lingzi,
Li Qun,
Patra Arghya,
Braun Paul V.
Publication year - 2019
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201901719
Subject(s) - electrolyte , materials science , electrode , x ray photoelectron spectroscopy , chemical engineering , electrochemistry , sulfide , cyclic voltammetry , fast ion conductor , interphase , analytical chemistry (journal) , chemistry , organic chemistry , biology , engineering , metallurgy , genetics
Solid‐state batteries can potentially enable new classes of electrode materials which are unstable against liquid electrolytes. Here, SnS nanocrystals, synthesized by a wet chemical method, are used to fabricate a Li‐ion electrode, and the electrochemical properties of this electrode are examined in both solid and liquid electrolyte designs. The SnS‐based solid‐state cell delivers a capacity of 629 mAh g −1 after 100 cycles and exhibits an unprecedentedly small irreversible capacity in the first cycle (8.2%), while the SnS‐based liquid cell shows a rapid capacity decay and large first cycle irreversible capacity (44.6%). Cyclic voltammetry (CV) experiments show significant solid electrolyte interphase (SEI) formation in the liquid cell during the first discharge while SEI formation by electrolyte reduction in the solid‐state cell appears negligible. Along with CV, X‐ray photoelectron spectroscopy and energy dispersive spectroscopy are used to investigate the differences between the solid‐state and liquid cells. The reaction chemistry of SnS in solid‐state cells is also studied in detail by ex situ X‐ray diffraction and X‐ray absorption spectroscopy. The overarching findings are that use of a solid electrolyte suppresses materials degradation and electrolyte reduction which leads to a small first cycle irreversible capacity and stable cycling.