Solid-state electrolytes for safe rechargeable lithium metal batteries: a strategic view

Abstract

Despite the efforts devoted to the identification of new electrode materials with higher specific capacities and electrolyte additives to mitigate the well-known limitations of current lithium-ion batteries (LIBs), this technology is believed to have almost reached its energy density limit. It suffers also of a severe safety concern ascribed to the use of flammable liquid-based electrolytes. In this regard, solid-state electrolytes (SSEs) enabling the use of lithium metal as anode in the so-called solid-state lithium metal batteries (SSLMBs) are considered as the most desirable solution to tackle the aforementioned limitations. This emerging technology has rapidly evolved in recent years thanks to the striking advances gained in the domain of electrolyte materials, where SSEs can be classified according to their core chemistry as organic, inorganic, and hybrid/composite electrolytes. This strategic review presents a critical analysis of the design strategies reported in the field of SSEs, summarizing their main advantages and disadvantages, and providing a future perspective toward the rapid development of SSLMB technology.

In Situ Formed Poly(ester-alt-acetal) Electrolytes with High Oxidation Potential and Electrode–Electrolyte Interface Stability

“…The Li + transference number ( t Li + ) was 0.85 as determined by a galvanostatic polarization method (Figure S10). This result suggests that the migration of Li + is dominant in the cell. ,, Besides the numerous Li + binding sites formed by in-chain alternating ester and acetal groups, the substantial t Li + can be ascribed to the supramolecular interactions between PEA and TFSI – . , With the introduction of LiTFSI, the C–H stretching vibration peak of PEA, initially observed at 2885–2962 cm –1 , shifts toward the lower wavenumbers (Figure S11), indicating the presence of supramolecular interactions between PEA and TFSI – . It is observed from Figure S12 that mutual interactions exist between O···H, F···H, O···C, and F···O in PEA with TFSI – , which significantly impede the migration of TFSI – . , In comparison, PDOL exhibits sole intermolecular interactions involving O···H and F···H with TFSI – .…”

“…51 This result suggests that the migration of Li + is dominant in the cell. 46,52,53 Besides the numerous Li + binding sites formed by in-chain alternating ester and acetal groups, the substantial t Li + can be ascribed to the supramolecular interactions between PEA and TFSI − . 54,55 With the introduction of LiTFSI, the C−H stretching vibration peak of PEA, initially observed at 2885− 2962 cm −1 , shifts toward the lower wavenumbers (Figure S11 On the other hand, the anodic stability of PEA-based PE was measured by linear sweep voltammetry (LSV) (Figure 4b).…”

Interfacial Modification of Ga-Substituted Li7La3Zr2O12 against Li Metal via a Simple Doping Method

“…6 The stability of solid electrolytes against Li metal provides a solution for realizing LMBs. 7 Since the initial report by Murugan in 2007, 8 the garnet-type Li 7 La 3 Zr 2 O 12 (LLZO) solid electrolyte has been extensively studied due to its high ionic conductivity, good thermal and chemical stabilities, environmental friendliness, and low cost. Garnet LLZO exists in two phases: the cubic phase (space group: Ia3̅ d) and the tetragonal phase (space group: I4 1 /acd).…”

“…Moreover, Li–metal batteries (LMBs), which directly employ metallic lithium as an anode, are considered promising due to the high theoretical capacity (3860 mA h g –1 ), low density, and low negative electrochemical potential (−3.04 V vs the standard hydrogen electrode) of Li metal . The stability of solid electrolytes against Li metal provides a solution for realizing LMBs …”

A high-performance TPGDA/PETEA composite gel polymer electrolyte for lithium metal batteries

“…8 The solid electrolytes have stable and nonflammable performances, while their robust mechanical strength can effectively inhibit the growth of lithium dendrites, and provide effective strategies to solve these problems. 9,10…”