Structural Interactions within Lithium Salt Solvates: Cyclic Carbonates and Esters

Only limited information is available regarding the manner in which cyclic carbonate and ester solvents coordinate Li+ cations in electrolyte solutions for lithium batteries. One approach to gleaning significant insight into these interactions is to examine crystalline solvate structures. To this end, eight new solvate structures are reported with ethylene carbonate, γ-butyrolactone, and γ-valerolactone: (EC)3:LiClO4, (EC)2:LiClO4, (EC)2:LiBF4, (GBL)4:LiPF6, (GBL)1:LiClO4, (GVL)1:LiClO4, (GBL)1:LiBF4, and (GBL)1:LiCF3SO3. The crystal structure of (EC)1:LiCF3SO3 is also re-reported for comparison. These structures enable the factors that govern the manner in which the ions are coordinated and the ion/solvent packingin the solid-stateto be scrutinized in detail.

目前关于锂电池电解液体系中环状碳酸酯与酯类溶剂配位锂离子（Li⁺）的具体方式，相关研究报道仍较为有限。获取此类溶剂-离子相互作用关键认知的有效途径之一，便是对结晶态溶剂化物结构展开研究。为此，本研究报道了8种基于碳酸乙烯酯（ethylene carbonate, EC）、γ-丁内酯（γ-butyrolactone, GBL）以及γ-戊内酯（γ-valerolactone, GVL）的新型溶剂化物结构，具体包括：(EC)₃:LiClO₄、(EC)₂:LiClO₄、(EC)₂:LiBF₄、(GBL)₄:LiPF₆、(GBL)₁:LiClO₄、(GVL)₁:LiClO₄、(GBL)₁:LiBF₄以及(GBL)₁:LiCF₃SO₃。此外，为便于对照比较，本研究还重新解析了(EC)₁:LiCF₃SO₃的晶体结构。通过上述溶剂化物结构，我们可对调控离子配位方式以及固态下离子-溶剂堆积行为的各类关键因素展开细致深入的剖析。