In Situ Grown MnO₂ Nanoflower Arrays on Ni Foam (MnO₂@NF) as 3D Lithiophilic Hosts for a Stable Lithium Metal Anode

Abstract

As the "holy grail" of lithium battery anode materials, the lithium metal anode suffers from several fatal defects, such as infinite volume expansion and uncontrolled dendrite formation. Herein, a three-dimensional (3D) lithiophilic host that comprises MnO 2 nanoflowers in situ grown on Ni foam (MnO 2 @NF) is developed into a stable lithium metal anode. The 3D porous structure of Ni foam (NF) can greatly reduce the average current density of the electrode and relieve volume changes during the repeated plating/stripping process, in which the MnO 2 nanoflower arrays endow the 3D framework with high lithiophilicity, leading to a reduced lithium nucleation barrier and uniform lithium nucleation. It is found that the MnO 2 nanoarrays could transform into Ni/Li 2 O, which offers abundant lithium deposition sites, homogenizes Li + flux distribution, and ensures fast Li + transfer kinetics. These advantages of MnO 2 @NF enable dendrite-free lithium deposition behavior and excellent electrochemical performance. As a consequence, the asdesigned MnO 2 @NF host delivers a high Coulombic efficiency (CE) of 98.7% for 400 cycles in a half cell under 0.5 mA cm −2 , and an ultralong cycling lifespan of 2000 h with a low-voltage hysteresis of 18 mV is achieved in a symmetrical cell at 1 mA cm −2 . Furthermore, the Li-MnO 2 @NF//LiFePO 4 full cell also exhibits enhanced cyclic stability and rate performance, indicating the application prospects of Li-MnO 2 @NF as a stable lithium metal anode.

Longan-Derived Biomass Carbon-Induced Cubic-Type Ferric Oxide Nanoparticles for Efficient Lithium-Ion Battery Anodes

“…In terms of various anode materials, transition metal oxides (e.g., Fe 2 O 3 , , Fe 3 O 4 , MnO 2 , − and ZnO − ) have become one class of key anode materials because of their low cost, higher specific capacity (theoretical value ≥600 mAh g –1 ) compared to graphite, and stable physical structure. Interestingly, Fe 2 O 3 is regarded as a promising candidate for LIB anode materials because of its high theoretical specific capacity of 1007 mAh g –1 and relatively low voltage platform compared to a large number of transition metal compounds (e.g., Co 3 O 4 , NiO, CuO, etc.…”

Integration of MnO2 Nanosheets with Pd Nanoparticles for Efficient CO2 Electroreduction to Methanol in Membrane Electrode Assembly Electrolyzers

“…Meanwhile, the other two peaks at 336.4 and 341.8 eV can be assigned to Pd 3d 5/2 and Pd 3d 3/2 of Pd 2+ , arising from an exposure of the sample to the air . The peaks of Mn 2p at 641.7 and 653.4 eV are Mn 2p 3/2 and Mn 2p 1/2 of Mn 4+ , respectively, with the satellite peak of Mn 4+ at 644.2 eV . The O 1s spectrum exhibits two peaks at 529.2 and 531.0 eV, representing the lattice oxygens bonded with Mn and the oxygen vacancies of metal unsaturated coordination, respectively, while another peak at 533.2 eV can be attributed to the oxygen peak of surface adsorbed water .…”

Review of Nanoarrays in Lithium Metal Anodes

“…The unique structure and strongly polarized surface provide abundant Li loading and make the NCO−CNF/Li electrode well reversible, and the abundant oxygen vacancies provide more lithophilic sites. In addition to this, Fan et al 144 designed the nanoflower array (Figure 4b) with Li plating/stripping high reversibility through a hydrothermal method, resulting in complete coverage of lithiophilic MnO 2 on the NF surface (MnO 2 @NF), which is transformed into Mn/Li 2 O with a unique structure during the initial cycling process (Figure 4c), providing the NF with abundant Li deposition sites. Due to the in situ generation of lithiophilic Mn, Li 2 O, in the lithium deposition process, the initial Li deposition maintains a uniform dense spherical form of nucleation, this deposition pattern can induce Li in the subsequent deposition process along the edge of the Li core deposition, with the increase in the amount of lithium plating, the gradual formation of dense block Li, the surface of the collector is not lithium dendrites generated.…”

“…(c) The characteristic peaks of Mn 2p were significantly shifted to lower binding energies after cycling, indicating that Mn (+4) was completely reduced to Mn (0). Reproduced with permission from ref . Copyright 2022 American Chemical Society.…”