Application of a Modified Porphyrin in a Polymer Electrolyte with Superior Properties for All-Solid-State Lithium Batteries

Porphyrins and their derivatives are a unique class of multifunctional and modifiable p-conjugated heterocyclic organic molecules, which have been widely applied in the fields of optoelectronic devices and catalysis. However, the application of porphyrins in polymer electrolytes for all-solid-state lithium-ion batteries (ASSLIBs) has rarely been reported. Herein, porphyrin molecules modified by polyether chains are used for composite solid-state polymer electrolytes (CSPEs) for the first time. The introduction of a modified porphyrin in an electrolyte can not only promote the electrochemical properties by constructing ordered ion channels via the intermolecular interaction between pi-conjugated heterocyclic porphyrins, but also significantly improve the mechanical strength and interface contact between the electrolyte membrane and the lithium metal anode. Consequently, the all-solid-state batteries assembled by the modified porphyrin composite polymer electrolyte, LiFePO4 cathodes, and Li anodes deliver a higher discharge capacity of 158.2 mA h g(-1) at 60 degrees C, 0.2 C, which remains at 153.6 mA h g(-1) after 120 cycles with an average coulombic efficiency of similar to 99.60%. Furthermore, the flexible porphyrin-based composite polymer electrolyte can also enable a Li parallel to LiCoO2 battery to exhibit a maximum discharge capacity of 108.6 mA h g(-1) at 60 degrees C, 0.1 C with an active material loading of 2-3 mg cm(-2), which is unable to realize for the corresponding batteries with a pure PEO-based polymer electrolyte. This work not only broadens the application scope of porphyrins, but also proposes a novel method to fabricate CSPEs with improved electrochemical and mechanical properties, which may shed new light on the development of CSPEs for next-generation high-energy-density lithium-ion batteries.

Automated summary

Porphyrins and their derivatives are unique multifunctional organic molecules that have been widely used in optoelectronic devices and catalysis. This study introduces modified porphyrin molecules to improve the electrochemical properties and mechanical strength of composite solid-state polymer electrolytes used in all-solid-state lithium-ion batteries. The batteries assembled with the modified porphyrin composite polymer electrolyte demonstrate higher discharge capacity and coulombic efficiency compared to those with pure PEO-based polymer electrolyte.