Inexpensive and eco-friendly nanostructured birnessite-type δ-MnO2: A design strategy from oxygen defect engineering and K+ pre-intercalation

A Flexible and Safe Planar Zinc‐Ion Micro‐Battery with Ultrahigh Energy Density Enabled by Interfacial Engineering for Wearable Sensing Systems

“…[19] In the case of Ce-MnO 2 , the characteristic peaks shift to lower wave numbers, indicating the decreased energy for the activation of MnO bonds, which might be attributed to the presence of oxygen defects in [MnO 6 ] octahedral. [20] In addition, the X-ray photoelectron spectroscopy (XPS) was measured to analyze the chemical compositions and the valence states of the samples. As shown in Figure S5a (Supporting Information), the characteristic peaks at ≈529.8 and 531.3 eV appear at the O 1s high-resolution XPS spectra of the two samples, corresponding to the lattice oxygen (blue) and the oxygen-deficient (orange) sites, respectively.…”

“…[ 19 ] In the case of Ce‐MnO 2 , the characteristic peaks shift to lower wave numbers, indicating the decreased energy for the activation of MnO bonds, which might be attributed to the presence of oxygen defects in [MnO 6 ] octahedral. [ 20 ]…”

Manganese Oxide Nanosheets with Mixed Valence States as a Separator Coating for Lithium–Sulfur Batteries

“…The O 1s spectra in Figure d display three identified peaks at 529.6, 530.5, and 532.6 eV, which are related to crystal oxygen (Mn–O–Mn), oxygen defects, and O–H bonds, respectively. It is noticed that the peak at 530.5 eV increases after annealing, indicating more oxygen defects formed in the treated MnO 2 . , The presence of both Mn 4+ and Mn 3+ valence states in MnO 2 contributes to an increase in electronic conductivity, primarily through the formation of a Mn 3+ –O–Mn 4+ pathway, which enhances electron mobility . As shown in Figure a, the treated MnO 2 shows much higher electronic conductivity than the pristine MnO 2 and pure Mn 2 O 3 , indicating the possible existence of a Mn 3+ –O–Mn 4+ route in the treated MnO 2 .…”

“…45,46 The Mn 3s spectra always show core-level peak splitting, and the energy separation of Mn 3s peaks exhibits a linear correlation with the oxidation state of Mn. As shown in Figure 2e,f 47,48 The presence of both Mn 4+ and Mn 3+ valence states in MnO 2 contributes to an increase in electronic conductivity, primarily through the formation of a Mn 3+ −O−Mn 4+ pathway, which enhances electron mobility. 49 As shown in Figure 3a, the treated MnO 2 shows much higher electronic conductivity than the pristine MnO 2 and pure Mn 2 O 3 , indicating the possible existence of a Mn 3+ −O−Mn 4+ route in the treated MnO 2 .…”

Structural Engineering of Vanadium Oxide Cathodes by Mn2+ Preintercalation for High-Performance Aqueous Zinc-Ion Batteries

“…For example, Cao et al achieved fast Zn 2+ transport by introducing K + ions into hydrated vanadium pentoxide and acted as a stabilizer to ensure cycling stability. Second, the introduction of oxygen vacancies is an effective means to accelerate the rate performance and improve reversible specific capacity for vanadium oxides, which originates from the unbalanced charge distribution caused by oxygen vacancies and the changed surface thermodynamics of the host material. ,, Third, heterostructure construction and composite with carbon-based materials can also achieve high electrochemical performance, which is attributed to the increase of active sites and the construction of conductive networks. ,, Although these strategies can improve the reversible specific capacity of vanadium-based oxide cathode materials, the strong electrostatic interaction of divalent ions is still the key that limits the rate performance. Meanwhile, the combination of various strategies often requires multistep reactions to be realized together .…”