Glassy Metal–Organic‐Framework‐Based Quasi‐Solid‐State Electrolyte for High‐Performance Lithium‐Metal Batteries

Abstract

Enhancing ionic conductivity of quasi‐solid‐state electrolytes (QSSEs) is one of the top priorities, while conventional metal–organic frameworks (MOFs) severely impede ion migration due to their abundant grain boundaries. Herein, ZIF‐4 glass, a subset of MOFs, is reported as QSSEs (LGZ) for lithium‐metal batteries. With lean Li content (0.12 wt%) and solvent amount (19.4 wt%), LGZ can achieve a remarkable ion conductivity of 1.61 × 10−4 S cm−1 at 30 °C, higher than those of crystalline ZIF‐4‐based QSSEs (LCZ, 8.21 × 10−5 S cm−1) and the reported QSSEs containing high Li contents (0.32–5.4 wt%) and huge plasticizer (30–70 wt%). Even at −56.6 °C, LGZ can still deliver a conductivity of 5.96 × 10−6 S cm−1 (vs 4.51 × 10−7 S cm−1 for LCZ). Owing to the grain boundary‐free and isotropic properties of glassy ZIF‐4, the facilitated ion conduction enables a homogeneous ion flux, suppressing Li dendrites. When paired with LiFePO4 cathode, LGZ cell demonstrates a prominent cycling capacity of 101 mAh g−1 for 500 cycles at 1 C with the near‐utility retention, outperforming LCZ (30.7 mAh g−1) and the explored MOF‐/covalent–organic frameworks (COF)‐based QSSEs. Hence, MOF glasses will be a potential platform for practical quasi‐solid‐state batteries in the future.

Laser-Derived Interfacial Confinement Enables Planar Growth of 2D SnS2 on Graphene for High-Flux Electron/Ion Bridging in Sodium Storage

“…S15 and Table S2). In contrast, A-SnS 2 @G possesses the lowest R ct value (57 Ω) compared with SnS 2 /G (141 Ω) and pure SnS 2 (270 Ω), indicative of the accelerated electron/ion migration by the covalent bridging effect [ 58 , 59 ]. The diffusion kinetics of Na + in different charge/discharge depths were evaluated in details by galvanostatic intermittent titration technique (GITT) in a coin cell after 50 cycles.…”

X‐ray Electron Density Study of the Chemical Bonding Origin of Glass Formation in Metal–Organic Frameworks**

“…Pure ZIF glasses as well as fabricated glass membranes with intrinsic permanent porosity are investigated as potential materials for gas mixture separations (H 2 /CH 4 , CO 2 /N 2 , and CO 2 /CH 4 , propane, propylene, and n‐butane) [9] and CO 2 adsorption [10] . ZIF glasses are also being explored as candidates for optical luminescence materials, [11] non‐linear optical materials, [12] quasi‐solid‐state‐electrolytes, [13] anode material in lithium‐ion batteries [14] or electrodes for oxygen evolution reaction [15] . Notably, ZIF glasses offer better processability for bulk application than crystalline powders [16] …”

Quantification of gas-accessible microporosity in metal-organic framework glasses

“…10,11 In recent years defective, disordered and amorphous MOFs have gained more and more attention since these materials provide access to new and unusual properties beyond the state of the art. [12][13][14][15][16][17][18][19][20] Especially solidto-liquid transitions of MOFs are exciting, as they offer processing and shaping of the framework materials in their liquid state (i.e. above their melting temperature, Tm) and vitrification to a MOF glass after cooling below their glass transition temperature (Tg).…”

“…above their melting temperature, Tm) and vitrification to a MOF glass after cooling below their glass transition temperature (Tg). [21][22][23][24][25] MOF glasses propose unique opportunities for solid state ion conduction 20,26,27 and gas separation membranes [28][29][30] because of improved performance as a result of their monolithic structure and the absence of mass transport limiting grain boundaries. 31 However, compared to their structurally well-defined crystalline parent materials, it is extremely difficult to predict and design the functionally relevant porosity features (pore volume and pore size) of the MOF glasses.…”