Metal Organic Framework Nanorod Doped Solid Polymer Electrolyte with Decreased Crystallinity for High‐Performance All‐Solid‐State Lithium Batteries

Abstract

Poly(ethylene oxide) (PEO), an important solid polymer electrolyte (SPE) for solid‐state lithium batteries, suffers from low ionic conductivity and poor electrochemical stability; many inorganic solid compounds have been explored as fillers to address these issues. Herein, we report that Al‐metal organic framework (MOF) nanorods could work as efficient solid fillers to boost the electrochemical performance of PEO‐based SPEs. The addition of MOF nanorods was found to inhibit the crystallization of PEO and effectively weaken the interactions among the PEO chains, resulting in evidently enhanced ionic conductivity and improved electrochemical stability; moreover, when embedded in PEO, such Al‐MOF nanorods are microporous and micrometer long, which are expected to favor the transportation of Li+ over the significantly more bulky anions TFSI−. Compared with pure PEO SPE, our optimal sample PEO‐MOF5% SPE has higher ion conductivity (2.09×10−5 S/cm at 30 °C and 7.11×10−4 S/cm 60 °C), a larger lithium‐ion transference number (0.46) and an enlarged electrochemical window (4.7 V versus Li/Li+). Accordingly, the cell of LiFePO4/PEO‐MOF5%/Li shows excellent cycle performance and rate performance. Our work proved the advantages of MOF particles as solid fillers towards high‐performance PEO‐based SPE, and we also put emphasis on the shape effect of the solid fillers on the lithium‐ion transference number and, thus, the electrochemical performance of the resulting SPE.

MOF-derived multifunctional filler reinforced polymer electrolyte for solid-state lithium batteries

“…The XRD diffraction (Fig. S6(a)) peak of the Co/HPCN functional filler has a weak signal in the PH and PILH, only 44.4°h as a weak diffraction peak, which may be due to the lower content [36]. The Raman spectra of the CSEs are shown in Fig.…”

“…A small amount of fillers is introduced into PEO polymer matrix, and the IC has increased due to the decrease of crystallinity of PEO. When the content of filler is further increased, the migration channel of Li + may be blocked, thereby reducing the IC of the electrolyte membrane [34,36]. According to Eqs.…”

Metal–organic frameworks and zeolite materials as active fillers for lithium-ion battery solid polymer electrolytes

“…Studies with the PEO host matrix have been carried out using different MOFs, with promising results. The addition of aluminum (Al)-MOF nanorods altered the properties of the matrix due to the strong interfacial interactions with the polymer chains, increasing the ionic conductivity and lithium transference number of the SPE when compared with pure PEO, and enlarging in parallel the electrochemical window up to 4.7 V. 140 The use of Zn 4 O(1,4-benzenedicarboxylate) (MOF-5) proved to stabilize the resistance in the interfaces of the tested cells and increased the cycling stability of the batteries up to 100 cycles. 144 This MOF is also able to significantly increase the lithium transference number and ionic conductivity of a TFEMA/PEGMA blend, due to the increase in the amorphous phase content and the microphase separation morphology caused by the addition of the MOF.…”

Boosting the Performance of Solid‐State Lithium Battery Based on Hybridizing Micron‐Sized LATP in a PEO/PVDF‐HFP Heterogeneous Polymer Matrix

“…[39] Differential scanning calorimetry (DSC) curves of PPL-0 and PPL-5 illustrate that the incorporation of micron-sized LATP can lower the melting temperatures of HSEs from 64.3 to 55.8 C. The crystallinity (χ c ) of electrolytes could be calculated by using Equation (1). [40]…”