“One Stone Two Birds” Design for Dual‐Functional TiO₂‐TiN Heterostructures Enabled Dendrite‐Free and Kinetics‐Enhanced Lithium–Sulfur Batteries

Abstract

Lithium–sulfur batteries (LSBs) are regarded as promising next‐generation energy storage systems owing to their remarkable theoretical energy density (2600 Wh kg‐1) and low cost. However, sluggish electrochemical kinetics, lithium polysulfides (LiPS) shuttling, and uncontrollable Li dendrite growth seriously hamper the commercial application of LSBs. Herein, dual‐functional 3D interconnected free‐standing fibers embedded with TiO2‐TiN heterostructures as an advanced skeleton are designed for concurrently regulating both the sulfur cathode (S/hollow TiO2‐TiN) and Li anode (Li/solid TiO2‐TiN). As a cathode skeleton, the hollow TiO2‐TiN fibers afford synergistic functions of chemical anchoring, physical confinement, and excellent electrocatalysis for LiPS. Meanwhile, the multifunctional skeleton with remarkable lithiophilicity and high conductivity can accomplish uniform Li deposition and homogeneous Li ion flux for inhibiting the growth of dendrites. Benefiting from these advantages, the full battery (S/hollow TiO2‐TiN || Li/solid TiO2‐TiN) exhibits excellent electrochemical performance, including high cycling stability (988.8 mAh g−1 after 200 cycles at 0.5 C) and impressive rate properties (639.3 mAh g−1 at 2 C). This work inaugurates a novel strategy from experimental and theoretical aspects for fabricating LSBs with robust electrochemical performance.

Mo2N Quantum Dots Decorated N‐Doped Graphene Nanosheets as Dual‐Functional Interlayer for Dendrite‐Free and Shuttle‐Free Lithium‐Sulfur Batteries

“…Surprisingly, an evident dendrite-free characteristic can be observed using Mo 2 N@NG/PP separator (Figure S8b,d, Supporting Information), proving a highly lithiophilic interface quality and desirably inhibited dendrite formation. [61,62] In brief, all the results synergistically verify that the Mo 2 N@NG contributes to facilitating uniform lithium nucleation and growth, which are derived from the improved interfacial conductivity and efficient chemical-physical limitation.…”

Lithiophilic Interphase Porous Buffer Layer toward Uniform Nucleation in Lithium Metal Anodes

“…The nucleation overpotential (µ n ) is defined as the gap between the "valley bottom" voltage and the stable voltage at the plating process. [33] Therefore, cells with GMM@Cu (≈5 mV) and MM@Cu (≈19.81 mV) exhibit lower nucleation overpotential than that with Mo 2 N@Cu (≈20.05 mV) and pure Cu foil (≈24.68 mV), which are virtues of abundant nucleation sites, fast electron charge transfer from BIEF, and electroplated guidance of Li 2 O and Li 3 N (Figure S4, Supporting Information). When the current is 1 mA cm -2 and capacity is increased to 1 mAh cm -2 , the cell with GMM@Cu can maintain good stability for more than 1090 cycles with CE > 99% (Figure 3a).…”

“…[31,32] Recently, in the lithium-sulfur batteries, there are heterojunctions based on Ti, V, and Nb capable of both adsorbing/ catalyzing polysulfides and inducing uniform deposition of the Li. [33][34][35] However, these reports immensely focus on the former and the heterojunctions have a small number of active sites for their small surface areas (<75 m 2 g -1 ). In addition, owing to the high surface energy, inorganic nanomaterials often suffer from aggregation.…”

A hierarchical VN/Co3ZnC@NCNT composite as a multifunctional integrated host for lithium–sulfur batteries with enriched adsorption sites and accelerated conversion kinetics

“…5e and Table S1. † [10][11][12][13]20,21,28,[49][50][51] The cycling performances of the four cathodes at 0.2C are compared in Fig. 5f.…”

“…15,16 Among various catalysts, transition metal nitrides (TMNs), such as Co 4 N, VN, TiN and MoN, have received signicant attention because of their high electrical conductivity and superior electrocatalytic activity. [17][18][19][20][21] Nevertheless, the performance of single component TMNs is still far from satisfactory owing to their insufficient specic surface area, limited number of active sites and inferior catalytic activity towards LiPSs. 22,23 In recent years, tremendous efforts have been made to further improve the performance of TMNs.…”