Hybrid polymer–liquid lithium ion electrolytes: effect of porosity on the ionic and molecular mobility

Abstract

Alternative electrolyte systems such as hybrid electrolytes are much sought after to overcome safety issues related to liquid electrolytes in lithium ion batteries (LIBs). Hybrid solid-liquid electrolytes (HEs) like the...

Ion transport, mechanical properties and relaxation dynamics in structural battery electrolytes consisting of an imidazolium protic ionic liquid confined into a methacrylate polymer

“…A conversion value of 94% ± 2% was estimated, a value slightly higher than that found from Raman spectroscopy but reasonably close. This value is the same for the samples prepared with and without the addition of the Li-TFSI salt and is also in agreement with values previously reported for equivalent materials, although analyzed by means of infrared spectroscopy [16] .…”

“…This system had an elastic modulus of about 360 MPa and an ionic conductivity of 0.2 mS/cm at ambient temperature [15] . In a subsequent study [16] , it was evidenced that a thermal curing processing route was beneficial for the synthesis of phase-separated methacrylate-based SBE films and structural electrodes, yielding a combination of improved thermo-mechanical properties (up to 750 MPa) and electrochemical performance, similar to that found in UV-cured ones. Nevertheless, the use of organic solvents is accompanied by safety issues related to their flammability and volatility, increasing the risk of fire and explosion, hence limiting the temperature range of safe operation.…”

“…Figure 10. Multifunctionality plot that compares the properties of the structural battery electrolyte investigated in this study (blue solid circle) with those of other equivalent electrolytes reported in the literature, all being based on bisphenol A epoxy resin but different liquid phases of ionic liquids [21,22,24,25] or organic solvents [15,16,18] . A solid electrolyte based on a cross-linked polystyrene (PS) polymer matrix and an ion-conducting phase consisting of a mixture of poly(ethylene oxide) (PEO) and an aprotic ionic liquid is also included in this comparative plot [26] .…”

“…One of the key challenges to achieving multifunctionality in structural batteries is the design of a suitable structural battery electrolyte (SBE), which simultaneously exhibits high Li-ion conductivity (σ dc > 1 mS/cm) and enables mechanical load transfer to the carbon fibers [13] . Since the pioneering study from 2007 by the US Army [14] , the scientific interest has turned to the design of novel microphase-separated heterogeneous structural electrolytes comprising two segregated phases: a glassy, rigid phase of a polymer matrix and a liquid ion-conducting phase that are independently responsible for the mechanical and the ion-conduction properties, respectively [13][14][15][16][17][18][19][20][21][22][23][24][25] . In this context, Ihrner et al established a phase-separated methacrylate-based SBE by a UV-cured synthetic method, in which the conductive phase consisted of an organic electrolyte [15] .…”

“…Figure 9. (A) Temperature dependence of the dc-conductivity (blue symbols), heat flow (rate = 10 K/min, magenta line), and mechanical storage moduli (green symbols, rate = 5 K/min, ω = 10 rad/s).The scale bar denotes the range of elastic storage moduli reported in the literature for SBEs with similar polymer matrices[13][14][15][16][17][18][19][20][21][22][23][24][25] . (B) Real part of the complex conductivity (solid lines) compared with the storage (filled circles) and loss (open circles) moduli at T = 318 K (T < T g ) (blue symbols) and T = 373 K (T > T g ) (red symbols).…”