A Triple‐Gradient Host for Long Cycling Lithium Metal Anodes at Ultrahigh Current Density

Abstract

The viable Li metal anodes (LMAs) are still hampered by the safety concerns resulting from fast Li dendrite growth and huge volume expansion during cycling. Herein, carbon nanofiber matrix anchored with MgZnO nanoparticles (MgZnO/CNF) is developed as a flexible triplegradient host for long cycling LMAs. The superlithiophilic MgZnO nanoparticles significantly increase the wettability of CNF for fast and homogeneous infusion with molten Li. The in-built potential and lithophilic gradients constructed after an in-situ lithiation of This article is protected by copyright. All rights reserved.MgZnO and CNF enable nearly zero Li nucleation overpotential and homogeneous deposition of lithium at different scales. As such, the LMAs based on MgZnO/CNF achieve long cycling life and small overpotential even at a record-high current density of 50 mA cm -2 and a high areal capacity of 10 mAh cm -2 . A full cell paring with this designed LMA and LiFePO 4 exhibits a capacity retention up to 82% after 600 cycles at a high rate of 5 C. A Liion capacitor also shows an impressive capacity retention of 84% at 5 A g -1 after 10000 cycles. Such a Li@MgZnO/CNF anode is a promising candidate for Li-metal energy storage systems, especially working under ultrahigh current density.

High-Coulombic-Efficiency Lithium Metal Anodes Enabled by Three-Dimensional Lithiophilic Nanostructures with Multiscale Porosity

“…This suggests that the Li plating in the NiO/Ni/CC matrix can be categorized into two subprocesses: NiO and carbon first react with Li + ions to form Li 2 O/Ni and LiC 6 . After lithiation, Li + ions are favorably plated from the Li 2 O surface to the nano- and microscale pores in/among nanobranches due to the dual-gradient of lithiophilicity and electrical conductivity induced by the carbon fibers, LiC 6 and Li 2 O/Ni, − thus preventing Li aggregation. As discussed in the SEM images, the macroscale interspaces between the carbon fibers are still preserved for Li + ion transport .…”

Gradient Design for High‐Energy and High‐Power Batteries

“…In practice, the gradient properties are usually realized by surface modification of the framework or varying the material composition along the thickness direction. [71][72][73]…”

Carbon/Lithium Composite Anode for Advanced Lithium Metal Batteries: Design, Progress, In Situ Characterization, and Perspectives

“…Therefore, the symmetrical cell of CNF-TiN/Li delivers a high capacity of 6 mA h cm −2 over 100 cycles and long-term life of 200 cycles at 3 mA cm −2 . In addition, some representative carbon fiber substrates prepared by electrospinning are also summarized in Table 5, including MgZnO/CNF-reduced graphene oxide, [180] Ag nanoparticle-embedded N-doped carbon macroporous fibers, [181] 3D conductive carbon nanofiber substrate with gradient-distributed ZnO particles, [182] ZIF-8 polyhedrons anchored on the oxidized polyacrylonitrile, [183] carbon nanofiber matrix anchored with MgZnO nanoparticles, [184] lotus root-like 3D multichannel carbon fibers decorated with Ag nanoparticles, [185] N-doped hollow carbon fiber/carbon nanosheets/ ZnO, [186] electrospinning oxygen-containing porous carbon nanofibers, [187] free-standing N-doped amorphous Zn-carbon multichannel fibers, [40] MOF-derived N/ZnO co-doped carbon substrates and embedded CNTs [188] and MCCNF@ZnO, [189] etc. It is believed that the unique advantages of electrospinning in obtaining adjustable flexible carbon structures to regulate Li deposition will be more enthusiastic for researchers.…”

“…MgZnO/CNF-reduced graphene oxide 1400 cycles, 1 mA h cm −2 at 5 mA cm −2 85 mA h g −1 after 500 cycles at 5 C [180] Ag nanoparticle-embedded N-doped carbon macroporous fibers 500 cycles, 1 mA h cm −2 at 1 mA cm −2 130 mA h g −1 after 250 cycles at 1C [181] 3D conductive carbon nanofiber substrate with gradient-distributed ZnO particles 900 cycles, 0.5 mA h cm −2 at 0.5 mA cm −2 115 mA h g −1 after 300 cycles at 5 C [182] ZIF-8 polyhedrons anchored on the oxidized polyacrylonitrile 300 cycles, 1 mA h cm −2 at 1 mA cm −2 140.8 mA h g −1 after 120 cycles at 6 C [183] Carbon nanofiber matrix anchored with MgZnO nanoparticles 500 cycles, 1 mA h cm −2 at 1 mA cm −2 87 mA h g −1 after 600 cycles at 100 mA g −1 [184] Lotus root-like 3D multichannel carbon fibers decorated with Ag nanoparticles 300 cycles, 1 mA h cm −2 at 1 mA cm −2 110 mA h g −1 after 600 cycles at 1 C [185] N-doped hollow carbon fiber/carbon nanosheets/ZnO 500 cycles, 1 mA h cm −2 at 1 mA cm −2 150 mA h g −1 after 500 cycles at 1 C [186] Electrospinning oxygen-containing porous carbon nanofibers 75 cycles, 1 mA h cm −2 at 0.5 mA cm −2 380 mA h g −1 after 100 cycles at 0.2C (Li-S) [187] Free-standing nitrogen doped amorphous Zn-carbon multichannel fibers 1000 cycles, 1 mA h cm −2 at 1 mA cm −2 138 mA h g −1 after 200 cycles at 1 C [40] MOF-derived N/ZnO co-doped carbon substrates and embedded carbon nanotubes 1000 cycles, 1 mA h cm −2 at 1 mA cm −2 121.7 mA h g −1 after 500 cycles at 1 C [188] MCCNF@ZnO 875 cycles, 1 mA h cm −2 at 0.5 mA cm −2 120 mA h g −1 after 200 cycles at 0.5 C [189] a thermal decomposition reaction of AgNO 3 into a carbon nanotube (Figure 12d). The particular structure of CNT/Ag uses the seeds of high lithiophilic Ag nanoparticles to enhance the lithiophilicity and high conductivity, reduce Li nucleation overpotential, and suppress Li dendrite formation effectively.…”