Biomimetic Synthesis of Ear‐of‐wheat‐shaped Manganese Oxide Nanoparticles on Carbon Nanotubes for High‐capacity Lithium Storage

Abstract

Manganese oxide (Mn3O4) is of great potential for lithium storage based on conversion reactions, but its application in rechargeable lithium batteries is severely hindered by the low electric conductivity and large volume variation during lithiation/delithiation. Herein, a biomimetic ear‐of‐wheat‐like nanocomposite of ultrafine Mn3O4 nanoparticles (MONPs) and multi‐walled carbon nanotubes (MWCNTs) is prepared using a facile solvothermal method. The tightly packed MONP “cereal‐grains” are directly grown and uniformly interspersed on the outer surface of skeleton MWCNT “central stems.” The ultrafine MONPs are favorable to lithium incorporation/extraction while the interconnected MWCNT skeletons provide a highly conducting network for electron transportation. Consequently, a high reversible capacity of 810 mA h g−1 is obtained at the current density of 40 mA g−1. After 50 cycles at 160 mA g−1, the nanocomposite still delivers a capacity up to 796 mA h g−1, which is higher than twice of that of pure Mn3O4 nanopowders. The unique nanostructure and the facile biomimetic method can be widely extended to design and explore various high‐performance energy materials for lithium/sodium ion batteries and fuel cells.

Oxygen-Tuned Na3V2(PO4)2F3–2yO2y (0 ≤ y < 1) as High-Rate Cathode Materials for Rechargeable Sodium Batteries

“…However, when the oxygen content is increased to a certain degree (0.5 < y < 1), the solid−gas equilibrium might be roughly achieved, and the Na 3 V 2 (PO 4 ) 2 F 3−2y O 2y particles tend to agglomerate to bigger particles with possibly thicker carbon coating. The homogeneously smaller particles could shorten the transmission distance of Na + during sodium extraction/insertion (charging/discharging) 45 and will no doubt improve the electrochemical performance of Na 3 V 2 (PO 4 ) 2 F 3−2y O 2y (0 ≤ y < 1). 1a).…”

Ultrafast Laser Drilling of 3D Porous Current Collectors for High-Capacity Electrodes of Rechargeable Batteries

“…EIS was fitted by the Zsimpwin program. Before the SEM imaging of cycled LiFePO 4 electrodes, the electrodes were disassembled in an Ar-filled glove box and rinsed with dimethyl carbonate (DMC) for several times …”

Off-Planar, Two-Dimensional Polymer Cathode for High-Rate, Durable Rechargeable Magnesium Batteries

“…The details of the synthetic procedure and electrode fabrication are mentioned in Section 2. SWCNT works as both conductive additive as well as active material, 56 although the capacity contribution (25 mAh g −1 at 100 mA g −1 ) is low for SWCNT alone (Figure S22). The rate performance of the composite electrode is shown in Figure 6e at different current densities, and the electrode is amenable to a high current discharge of up to 5000 mA g −1 .…”