Enhanced Cyclability of Lithium Metal Anodes Enabled by Anti-aggregation of Lithiophilic Seeds

Abstract

Constructing 3D skeletons modified with lithiophilic seeds has proven effective in achieving dendrite-free lithium metal anodes. However, these lithiophilic seeds are mostly alloy-or conversion-type materials, and they tend to aggregate and redistribute during cycling, resulting in the failure of regulating Li deposition. Herein, we address this crucial but long-neglected issue by using intercalation-type lithiophilic seeds, which enable antiaggregation owing to their negligible volume expansion and high electrochemical stability against Li. To exemplify this, a 3D carbon-based host is built, in which ultrafine TiO 2 seeds are uniformly embedded in nitrogendoped hollow porous carbon spheres (N-HPCSs). The TiO 2 @N-HPCSs electrode exhibits superior Coulombic efficiency, high-rate capability, and long-term stability when evaluated as compertitive anodes for Li metal batteries. Furthermore, the superiority of intercalation-type seeds is comprehensively revealed through controlled experiments by various in situ/ex situ electron and optical microscopies, which highlights the excellent structural stability and lithiophilicity of TiO 2 nanoseeds upon repeated cycling.

Spatially Distributed Lithiophilic Gradient in Low‐Tortuosity 3D Hosts via Capillary Action for High‐Performance Li Metal Anodes

“…More impressively, even if the current density increases to 10 mA cm −2 , the WDC-GDAg battery can still cycle over 200 h without short circuits, which is far beyond the cycling life of the WDC and Li foil (Figure 3e; Figure S16, Supporting Information). This remarkable cycling stability and rate performance endow the gradient-distributed 3D structures with great competitiveness among the everreported lithium metal modulation strategies in the latest literature [17,31,50,51,[67][68][69][70][71][72][73][74] (Figure S17, Supporting Information).…”

Sequential and Dendrite‐Free Li Plating on Cu Foil Enabled by an Ultrathin Yolk–Shell SiOx/C@C Layer

“…Meanwhile, the spherical morphology of SiO x /C@C is well maintained after cycling, without dissolution or aggregation problems such as lithiophilic Au or Ag "seeds" (Figure S11, Supporting Information). [22,42] Reviewing the whole lithiation/Li plating process of yolk-shell SiO x /C@C as shown in Video S1, Supporting Information; Figure 3a, it is observed that the Li deposition always begins at the interface, that is to say, the contact point between SiO x /C core and N,S co-doped C shell (indicated by the red circle in Figure 3c).…”

“…[ 17–21 ] The aggregation or dissolution of these materials during cycling will lead to insufficient regulation effects and inaccessible voids for Li deposition. Besides, some oxide‐based lithiophilic “sites” (TiO 2 , SiO x /C) have also been employed to regulate the Li deposition, demonstrating better structural stability than the above‐mentioned metallic lithiophilic “sites.” [ 22,23 ] Doping the carbon materials with foreign atoms can also improve the lithiophilicity; [ 24–26 ] however, as Li is deposited only on the surface of the hollow carbon without entering it, [ 27 ] Li dendrites will form as well when the deposited Li increases (Scheme 1b). Due to the insufficiently utilized void space, the Li storage capacities are usually low (<3 mAh cm −2 ) before the dendrite is formed.…”

Advances in Nanofibrous Materials for Stable Lithium-Metal Anodes

“…Carbon nanofibers (CNFs) usually have high specific surface area, rich pore structure, excellent chemical stability, and high electrical conductivity and, as artificial protective layers, have been shown to effectively reduce local current density and regulate lithium deposition. − For example, the carbonized silk nanofiber (SCNF) films were used as double interlayers of lithium-sulfur batteries, which could inhibit the growth of lithium dendrites on the LMA side and block dissolved polysulfides on the sulfur cathode side to reduce their corrosion to lithium metal (Figure a) . In addition, the doping of nanoparticles or nanosheets into carbon-based materials as heterogeneous seeds can effectively guide lithium deposition and achieve spatial control of lithium nucleation, which is a common tactic to enhance the lithiophilicity of carbon-based protective layers. − As shown in Figure b, Wei and co-workers manufactured ordered carbon nanofiber films (MnS@CNC/CNFs) doped with MnS nanoparticles and cellulose nanocrystalline (CNC) by microfluidic spinning techniques and carbonization processes . The MnS nanoparticles in the fiber film underwent similar alloying reaction with Li + , and the polar functional group (−OH) in the CNC had a strong adsorption effect on Li + , which could guide Li + to be uniformly plated on the electrode surface, thus effectively inhibiting the formation of dendritic lithium (Figure c).…”