A Hierarchical Silver‐Nanowire–Graphene Host Enabling Ultrahigh Rates and Superior Long‐Term Cycling of Lithium‐Metal Composite Anodes

Abstract

Although lithium (Li)-ion batteries have achieved great success in commercialization for sustainable and clean energy applications including portable electronics, electric transportation, and grid-scale energy storage, existing battery systems of graphitebased anodes and transition metal oxide-based cathodes hardly meet the increasing requirements for higher energy and power densities. [1][2][3][4] Li metal has a high theoretical capacity Metallic lithium (Li) is a promising anode for next-generation high-energydensity batteries, but its applications are still hampered due to the limited charging/discharging rate and poor cycling performance. Here, a hierarchical 3D porous architecture is designed with a binary network of continuous silver nanowires assembled on an interconnected 3D graphene skeleton as the host for Li-metal composite anodes, which offers a significant boost in both charging/discharging rates and long-term cycling performance for Li-metal batteries. This unique hierarchical binary network structure in conjunction with optimized material combination provides ultrafast, continuous, and smooth electron transportation channel and non-nucleation barrier sites to direct and confine Li deposition. It also offers outstanding mechanical strength and toughness to support massive Li deposition and buffer the internal stress fluctuations during long-term repeated Li stripping/plating thereby minimizing fundamental issues of dendrite formation and volume change even under ultrafast charging/discharging rates. As a result, the composite anode using this hierarchical host can work smoothly at an unprecedented high current density of 40 mA cm -2 over 1000 plating/stripping cycles with low overpotential (<120 mV) in symmetric cells. The as-constructed full cell, paired with LiNi 0.5 Co 0.2 Mn 0.3 O 2 cathode, also exhibits excellent rate capability and high-rate cycling stability.(3860 mAh g −1 ) and low electrochemical potential (−3.04 V vs the standard hydrogen electrode) and is thus perceived as an ideal anode for next-generation rechargeable batteries-especially for Li-sulfur and Li-oxygen battery systems. [5][6][7][8] However, the use of a Li-metal anode in advanced battery systems for stable and ultrafast charging/discharging is severely restricted by safety and cyclability concerns caused by dendritic Li formation, infinite volume change, and instability of solid electrolyte interphase (SEI). This has limited the practical use of Li-metal batteries for many decades. [9][10][11][12][13] Several strategies focused on constructing stable and uniform SEI layer on Li anode have been explored to tolerate the huge volume change and suppress the formation of dendritic Li. Examples include optimizing the electrolyte contents, modifying he Li anode surface, and developing artificial coatings on the anode surface. [10,[13][14][15][16] Despite the great success achieved on the rational design of SEI layer, the nature of Li dendrite formation arising from inhomogeneous Li-ion flux distribution on planar Li foil or copp...

3D‐Printed Stretchable Micro‐Supercapacitor with Remarkable Areal Performance

“…The fabrication process of the intrinsically stretchable MSC, as illustrated in Figure 1 , begins with the formulation of viscous pseudoplastic MXene‐based electrode ink for extrusion‐based 3D printing according to the modified nanocomposite gelation strategies . Hydrophilic and delaminated Ti 3 C 2 T x MXene nanosheets were first prepared by selectively etching bulk Ti 3 AlC 2 MAX followed by exfoliation in distilled water .…”

“…A dilute and uniformly dispersed mixture of MXene, AgNWs, MnONWs, and C60 was then prepared through mild ultrasonication, followed by vacuum filtration to obtain a MXene‐AgNW‐MnONW‐C60 hydrogel. After redispersion in distilled water, the 1D AgNWs and MnONWs can associate with the flexible and hydrophilic 2D MXene nanosheets to form a dynamic cross‐linked 3D network . This network facilitates the gelation of the printable nanocomposite ink without the need of any organic dispersing and rheological agents .…”

Key Aspects of Lithium Metal Anodes for Lithium Metal Batteries

“…Although, constraining Li within a porous host by controlling the deposition by seeds has proven to be an effective way of reducing the local current density, accommodating volume changes and inhibiting dendrite growth, further improvement is required to achieve more stable Li anodes with high Li plating/stripping rates and a long cycle life to produce acceptable Li metal batteries. To overcome the limitations of low current density charge/discharge, Liang and co‐workers demonstrated a silver nanowire and graphene‐based binary network (AGBN) as a host for the uniform electrodeposition of Li. In this material, the silver nanowires provide a large surface area, high electrical conductivity and act as seeds for Li deposition, whereas the graphene scaffold gives the electrode mechanical strength and maintains its structural integrity during fast cycling.…”

“…b) Nucleation overpotential of a Li foil (blue) and a Li@3D–AGBN composite anode. Rate performance of bare Li–Cu and 3D‐AGBN anodes with NCM cathodes c) at 10 C and d) at 20 C. Reproduced with permission . Copyright 2018, Wiley‐VCH.…”

Superlithiophilic Amorphous SiO2–TiO2 Distributed into Porous Carbon Skeleton Enabling Uniform Lithium Deposition for Stable Lithium Metal Batteries

“…[2,[6][7][8][9][10][11] However, even with the aid of these interfacial layers, uniform deposition is difficult as it is dependent on a plethora of external factors including ion diffusion, screw dislocation of atoms, and the morphology of the electrode surface. [14][15][16][17][18][19][20][21][22][23][24][25] This specific technique offers several advantages: [26] 1) the porous structure reduces the local current density and ensures sufficient Li ion flux; 2) the porous 3D skeleton accommodates the volumetric change of the Li anode during the plating and stripping progress; 3) Li is deposited on the interior of the 3D matrices, but not directly on the surface of the electrode, thus prohibiting dendrite growth. [14][15][16][17][18][19][20][21][22][23][24][25] This specific technique offers several advantages: [26] 1) the porous structure reduces the local current density and ensures sufficient Li ion flux; 2) the porous 3D skeleton accommodates the volumetric change of the Li anode during the plating and stripping progress; 3) Li is deposited on the interior of the 3D matrices, but not directly on the surface of the electrode, thus prohibiting dendrite growth.…”