Unusual Inside–Outside Li Deposition within Three-Dimensional Honeycomb-like Hierarchical Nitrogen-Doped Framework for a Dendrite-Free Lithium Metal Anode

Abstract

Lithium (Li) metal batteries have attracted massive research interest as candidates for a high energy density system. However, the instability and dendrite issue of Li metal have substantially hindered their practical applications. Therefore, we proposed a well-designed three-dimensional honeycomb-like hierarchical nitrogen (N)-doped framework (HHNF) as a matrix for Li deposition. Many Li ions can be distributed and reduced uniformly through the strong adsorption of N-containing functional groups in the HHNF. Metallic Li deposition on the HHNF follows an “inside–outside” mechanism, and the deposited Li spreads evenly on a flat surface when the internal porous space is filled completely. In this work, homogeneous Li deposition and the avoidance of Li dendrite formation are demonstrated by in situ optical microscopy and in situ Raman spectroscopy. The HHNF performs a high and stable Coulombic efficiency (98.5%) within 400 cycles and an ultralong lifespan of 1000 h at 0.5 mA cm–2 with a low potential polarization (23.8 mV) according to the symmetric cell test. In addition, full cells based on HHNF@Li anodes and LiFePO4/sulfur cathodes exhibit outstanding reversible capacities and rate performance (144.1 mAh g–1 for LiFePO4 after 150 cycles and 676.2 mAh g–1 for sulfur after 100 cycles at 0.5 C).

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

“…Therefore, the peaks related to defects and graphite domains gradually recovered, indicating the reversible Li plating/stripping process on the L‐DG. Similar conclusions were further confirmed by Wang's group [ 208,209 ] and Xie's group, [ 210 ] etc. In addition, the components of SEI can also be detected by in situ Raman spectroscopy.…”

Transferring Liquid Metal to form a Hybrid Solid Electrolyte via a Wettability‐Tuning Technology for Lithium‐Metal Anodes

“…The ever-increasing demands for highenergy-density batteries have motivated intensive studies on rechargeable Li-metal batteries in recent years because Li-metal anodes have an exceedingly high specific capacity (3860 mAh g −1 ) and low electrode potentials (−3.04 V vs the standard hydrogen electrode). [1][2][3][4][5] However, Li-metal anodes suffer from several severe issues in practical applications, [6][7][8][9][10] such as high surface area lithium growth, [11][12][13][14][15] rapid consumption of active Li, [16][17][18] and accumulation of solid electrolyte interphase (SEI), [19][20][21][22] which lead to safety concerns, short cycle life, and low Coulombic efficiency (CE). Owing to the high activity, Li metal spontaneously reacts with most electrolytes if it is not passivated or protected.…”

Advances in the Emerging Gradient Designs of Li Metal Hosts

“…Under a practical current density of 3.0 mA cm −2 at 1.0 mAh cm −2 , the average CE of the battery reaches 97.4% over 120 cycles ( Figure 3(e) ). Subsequently, a honeycomb-like hierarchical nitrogen-doped framework (HHNF) electrode was obtained by annealing PAN-coated Cu foil [ 71 ]. In this case, the pores promote the even distribution of electrons, while the lithiophilic N dopants guide homogeneous Li nucleation and deposition, leading to an “inside-outside” Li deposition pattern without dendrite formation in HHNF.…”