Xiong Song,Guoping Chen,Suqing Wang,Yuping Huang,Zhouyang Jiang,Liang-Xin Ding,Haihui Wang
Separator modification has been proved to be an effective approach for overcoming lithium polysulfide (LiPS) shuttling in lithium–sulfur (Li–S) cells. However, the weight and stability of the modified layer also affect the cycling properties and the energy density of Li–S cells. Here, we initially construct an ultrathin and lightweight MnO2 layer (380 nm, 0.014 mg cm–2) on a commercial polyethylene (PE) separator (MnO2@PE) through a chemical self-assembly method. This MnO2 layer is tightly anchored onto the PE substrate because of the presence of oxygen-containing groups that form a relatively strong chemical force between the MnO2 nanoparticles and the PE substrate. In addition, the mechanical strength of the separator is not affected by this modification procedure. Moreover, because of the catalytic effect and compactness of the MnO2 layer, the MnO2@PE separator can greatly suppress LiPS shuttling. As a result, the application of this MnO2@PE separator in Li–S batteries leads to high reversible capacity and superior cycling stability. This strategy provides a novel approach to separator surface modification.
Emerging nanotechnologies in cancer therapy increasingly highlight the importance of integrating therapeutic and diagnostic functions into a single platform for enhanced efficacy and real-time monitoring. Here, we present a vortex‐shaped nanoring Fe 3 O 4 @MnO 2 @PDA (polydopamine) engineered for dual‐mode T 1 – T 2 magnetic resonance imaging (MRI)‐guided, dual‐thermal, and Fenton‐like chemodynamic therapy (CDT). The ring‐shaped nano Fe 3 O 4 core provides magnetothermal hyperthermia, while the MnO 2 layer, acting as a responsive nanozyme, catalyzes endogenous H 2 O 2 to generate oxygen and bolster CDT. Meanwhile, the PDA coating efficiently absorbs near‐infrared light, amplifying photothermal effects for tumor ablation. Under dual‐heating conditions, the temperature rise rate (2.05–2.92 times) and final equilibrium temperatures (1.57–2.27 times) exceed those of single‐mode heating, underscoring a robust synergistic effect. Additionally, due to the shell’s shielding effect weakening T 2 signals and the tumor microenvironment enhancing T 1 relaxation, the T 1 (5.75 Mm −1 s −1 ) to T 2 (91.56 mM −1 s −1 ) ratio is optimized specifically at tumor sites, thus achieving effective dual‐modal MRI contrast. Moreover, the smart MnO 2 design not only furnishes dynamic imaging enhancements but also enables environment‐triggered Mn 2+ release, offering further diagnostic and therapeutic benefits. In vitro and in vivo evaluations confirm significant tumor suppression with minimal systemic toxicity. These findings position nanoring Fe 3 O 4 @MnO 2 @PDA as a promising dual‐mode MRI‐guided, dual‐thermal, and chemodynamic platform for advanced cancer therapy.
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