Electrospinning Equipment for Research| Framework Integration for Adaptive Interfaces in FlexibleSolid-state Lithium-0xygen Batteries

Professor Zhou Zhen & Researcher Zhang Zhang from Zhengzhou University《Angew》: Adaptive Interface Design Enables Breakthrough in Flexible Solid-State Li-O₂ Batteries

Lithium-oxygen (Li-O₂) batteries, with their ultrahigh theoretical energy density of 3500 Wh/kg, are recognized as a leading candidate for next-generation high-energy-density storage technologies. However, conventional Li-O₂ batteries employing organic liquid electrolytes suffer from inherent drawbacks including flammability, volatility, and poor chemical stability, which severely limit their safety and long-term performance.Solid polymer electrolytes (SPEs) offer potential advantages in enhancing safety and interface compatibility, partially addressing these issues. Nevertheless, SPEs commonly face challenges such as poor electrode contact and high interfacial impedance, resulting in constrained electrochemical performance. Therefore, constructing stable and efficient electrode-electrolyte interfaces has become a critical scientific challenge and engineering bottleneck for improving solid-state Li-O₂ battery performance.

Recently, Professor Zhou Zhen and Researcher Zhang Zhang's team at Zhengzhou University published their latest research titled "Framework Integration for Adaptive Interfaces in Flexible Solid-State Lithium-Oxygen Batteries" in *Angewandte Chemie International Edition*. The researchers prepared self-supporting carbon nanofibers (CNFs) via electrospinning and thermal treatment, then modified them with polyelectrolyte PDDA to obtain PDDA-CNF (P-CNF) cathodes. Through electrostatic adsorption, they successfully constructed an integrated and coordinated structure (IPC). 

Figure 1: Preparation and characterization of the functional integrated structure

Zeta potential and XPS analyses confirmed successful polyelectrolyte functionalization of the cathode.This structure achieves stable adaptive interfaces through coherent architectural design, enabling high ionic transport pathways that significantly reduce interfacial resistance while constructing continuous and abundant three-phase interfaces to maximize active area. Moreover, the cathode preparation requires no additional binder, allowing all internal electrode components to participate in electrochemical reactions. This integrated structure not only enhances overall electrode energy density but also significantly extends battery cycle life, demonstrating its potential in high-performance energy storage devices.

Figure 2: Interfacial reaction kinetics of Li⁺ transport  

Solid-state NMR, XPS, and molecular dynamics simulations were employed to study the local environment of LiTFSI in CNF- and IPC-based Li-O₂ batteries. Results show PDDA promotes LiTFSI dissociation, thereby accelerating Li⁺ transport. From a kinetic perspective, the mean square displacement of Li⁺ and calculated self-diffusion coefficients confirm PDDA addition enhances Li⁺ free diffusion.

Figure 3: Electrochemical performance of IPC-based Li-O₂ batteries  

Electrochemical tests on different Li-O₂ battery structures reveal that flexible solid-state lithium-oxygen batteries (SSLOBs) with IPC architecture demonstrate high specific capacity (8600 mAh/g) and stable cycling (191 cycles), maintaining good stability even at high current densities. This superior performance primarily stems from the adaptive interfaces formed during cycling, which spontaneously regulate and maintain stable, tight contact between electrolyte and cathode while establishing continuous, efficient ion transport channels. These dynamic regulation behaviors align perfectly with structural characterization results, fully validating IPC's significant synergistic enhancement in interface stability and electrochemical performance.

Figure 4: Stability tests of IPC-based Li anodes

Figure 5: Reversibility analysis of Li-O₂ batteries  

Figure 6: Applications of flexible Li-O₂ batteries  

The IPC structure effectively anchors anions, significantly accelerating Li⁺ transport and promoting formation of inorganic-rich stable SEI layers, thereby suppressing Li dendrite growth and enabling uniform, stable Li deposition. Meanwhile, on IPC-based cathodes, discharge products distribute uniformly as unique nanoparticles on carbon fiber surfaces and undergo highly reversible decomposition during charging. This special discharge product distribution maintains full contact with abundant active sites and enables rapid charge transfer during charging, resulting in low charge overpotential.Furthermore, flexible Li-O₂ batteries constructed with IPC architecture exhibit excellent bending resistance, maintaining high performance output while demonstrating good mechanical flexibility, showing promising practical application prospects. Notably, this integrated coordinated structure also shows excellent performance in other energy storage systems, further validating its design feasibility and universality while providing effective interface construction strategies for various high-performance energy storage devices.

Paper link: https://doi.org/10.1002/anie.202507660