Grafted MXenes Based Electrolytes for 5V‐Class Solid‐State Batteries

Abstract

Polymer blends based solid polymer electrolytes (SPEs), combining the advantages of multiple polymers, are promising for the utilization of 5 V‐class cathodes (e.g., LiCoMnO4 (LCMO)) with enhanced safety. However, severe macro‐phase separation with defects and voids in polymer blends restrict the electrochemical stability and ionic migration of SPEs. Herein, inorganic compatibilizer polyacrylonitrile grafted MXene (MXene‐g‐PAN) is exploited to improve the miscibility of the poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVHF)/PAN blends and suppress the consolidation of phase particles. The resulting SPE exhibits a high anodic stability with an ionic conductivity of 2.17 × 10−4 S cm−1, enabling a stable and reversible Li platting/stripping (over 2500 h). The fabricated solid Li‖LCMO cell delivers a 5.1 V discharge voltage with a decent capacity (131 mAh g−1) and cycling performance. Subsequently, the solid all‐in‐one graphite‖LCMO battery is also constructed to extend the application of MXene based SPEs in flexible batteries. Benefiting from the interface‐less design, outstanding mechanical flexibility and stability is achieved in the battery, which can endure various deformations with a low‐capacity loss (< ≈10%). This study signifies a significant development on solid flexible lithium ion batteries with enhanced performance, stability, and reliability by investigating the miscibility of polymer blends, benefiting for the design of high‐performance SPEs.

Recent advances in designing solid-state electrolytes to reduce the working temperature of lithium batteries

“…Chen added the inorganic compatibilizer to the PAN/PVDF-HFP blend system, which had the effect of improving the phase interface of the polymer and eliminating the phase agglomeration phenomenon. This method obtained an ionic conductivity of 2.17 × 10 −4 S cm −1 and a discharge voltage of up to 5.1 V. 75…”

“…Chen added the inorganic compatibilizer to the PAN/PVDF-HFP blend system, which had the effect of improving the phase interface of the polymer and eliminating the phase agglomeration phenomenon. This method obtained an ionic conductivity of 2.17 Â 10 À4 S cm À1 and a discharge voltage of up to 5.1 V. 75 In addition, simply changing the size and content of the filler is not enough. There is a large amount of operable space on the particle surface.…”

Practical challenges and future perspectives of solid polymer electrolytes: microscopic structure and interface design

“…However, it is important to note that the overall performance of blended SPEs can be hampered by pronounced macro-phase separation induced by structural defects and voids, ultimately restricting both electrochemical stability and ionic mobility within the SPEs. 143 In this context, a judiciously engineered supramolecular polymer, incorporating both hard and soft segments interconnected through hydrogen bonds, emerges as a promising solution to circumvent the issue of macrophase separation within blended SPEs. As we all know, supramolecular polymers are polymeric arrays of monomer units connected by reversible and highly directed secondary interactions (i.e., non-covalent bonds).…”

Coupling Anion‐Capturer with Polymer Chains in Fireproof Gel Polymer Electrolyte Enables Dendrite‐Free Sodium Metal Batteries

“…[34][35][36][37] However, simply physical mixing inorganic fillers into the electrolyte leads to the problems of agglomeration of fillers and phase separation between inorganic fillers and polymer, which limit the improvement of electrochemical performance of composite electrolyte to some extent. [38] In addition, GPEs also exhibit poor interfacial stability due to the simultaneous transport of cations and anions in electrolyte, the free transport of anions leads to large concentration polarization and space charge layer at the anode side, resulting in unsatisfactory interfacial compatibility and uncontrolled growth of Na dendrites. Therefore, it remains challenging to achieve a GPE that integrates high ionic conductivity, excellent mechanical properties, superior interfacial stability, and safety without making tradeoffs among these properties.…”