ZIF-8-Based Quasi-Solid-State Electrolyte for Lithium Batteries

Abstract

The quasi-solid-state electrolytes (QSSEs) with an inorganic skeleton, a solid−liquid composite material combining their respective merits, exhibit high ionic conductivity and mechanical strength. However, most quasi-solid electrolytes prepared by immobilizing ionic liquid (IL) or organic liquid electrolyte in inorganic scaffold generally have poor interface compatibility and low lithium ion migration number, which limits its application. Herein, we design and prepare a ZIF-8-based QSSE (ZIF-8 QSSE) in which the ZIF-8 has a special cage structure and interaction with the guest electrolyte to form a composite electrolyte with good ionic conductivity about 1.05 × 10 −4 S cm −1 and a higher lithium-ion transference number of about 0.52. With the ZIF-8 QSSE, a protype lithium battery coupled with LiCoO 2 cathode shows good electrochemical performances with an initial discharge capacity of 135 mAh g −1 at 50 mA g −1 and a remaining capacity of 119 mAh g −1 after 100 cycles, only 0.119% capacity degradation per cycle. It is worth noting that the ZIF-8-based QSSEs have good thermal stability up to 350 °C that does not show thermal runaway, which is significantly higher than that of a conventional organic liquid battery system.

Comparison of the ionic conductivity properties of microporous and mesoporous MOFs infiltrated with a Na-ion containing IL mixture

“…Recently, reports on the full battery performance of lithium salt based IL@MOF composites have been demonstrated in the literature for a range of configurations such as Li|LiIL@MOF|Li symmetric cells, Li|LiIL@MOF|LiFePO4 and Li|LiIL@MOF|LiCoO2 cells. 2,4,54 These early results show promising electrochemical performance, with little capacity degradation upon cycling and good thermal stability. 2,4,54 From the comparisons made here, we have seen that the nature of the MOF pores has a substantial impact on the ionic conductivities of the composite material.…”

“…2,4,54 These early results show promising electrochemical performance, with little capacity degradation upon cycling and good thermal stability. 2,4,54 From the comparisons made here, we have seen that the nature of the MOF pores has a substantial impact on the ionic conductivities of the composite material. Perhaps the ideal MOF structure for such a composite would consist of an ordered hierarchical porosity with micro-and meso/macroporous pathways which are long-range and continuous on all length scales.…”

Metal/covalent‐organic frameworks for electrochemical energy storage applications

“…Thus, IL as an efficient ions carrier is introduced to MOF-derived SSE to improve the ion conductivity. [264][265][266] Kitagawa et al 267 devoted much effect to incorporate ionic liquids with MOF and make a conclusion of the development of IL and MOF composites. They reported the behavior of EMI-TFSA in ZIF-8 268,269 and explored the lithium-ion conductivity in this material.…”

Lithium-, Sodium-, and Potassium-ion Conduction in Polymeric and Discrete Coordination Systems

“…as a counterion. 68 They introduced LiPF 6 into zirconium-MOF ZIF-8 (Zn(MeIM) 2 ; MeIM = 2-methylimidazolate) 69 in the presence of organic solvents (EC/DMC/EMC = 1:1:1, DMC = dimethyl carbonate, EMC = ethylmethyl carbonate). However, the conductivity was not as high (1.05 © 10 ¹4 S cm ¹1 at 25°C) as a perchlorate system.…”