Lithium-metal batteries (LMBs), as one of the most promising next-generation high-energy-density storage devices, are able to meet the rigid demands of new industries. However, the direct utilization of metallic lithium can induce harsh safety issues, inferior rate and cycle performance, or anode pulverization inside the cells. These drawbacks severely hinder the commercialization of LMBs. Here, an up-to-date review of the behavior of lithium ions upon deposition/dissolution, and the failure mechanisms of lithium-metal anodes is presented. It has been shown that the primary causes consist of the growth of lithium dendrites due to large polarization and a strong electric field at the vicinity of the anode, the hyperactivity of metallic lithium, and hostless infinite volume changes upon cycling. The recent advances in liquid organic electrolyte (LOE) systems through modulating the local current density, anion depletion, lithium flux, the anode-electrolyte interface, or the mechanical strength of the interlayers are highlighted. Concrete strategies including tailoring the anode structures, optimizing the electrolytes, building artificial anode-electrolyte interfaces, and functionalizing the protective interlayers are summarized in detail. Furthermore, the challenges remaining in LOE systems are outlined, and the future perspectives of introducing solid-state electrolytes to radically address safety issues are presented.

Urea electrooxidation with favorable thermodynamic potential offers great promise for decoupling H2/O2 evolution from sluggish water splitting, and simultaneously mitigating the problem of urea‐rich water pollution. However, the intrinsically slow kinetics of the six‐electron transfer process impels one to explore efficient catalysts in order to enable widespread use of this catalytic system. In response, taking CoS2/MoS2 Schottky heterojunctions as the proof‐of‐concept paradigm, a catalytic model to modulate the surface charge distribution for synergistically facilitating the adsorption and fracture of chemical group in urea molecule is proposed and the mechanism of urea electrooxidation at the molecular level is elucidated. Based on density functional calculations, the self‐driven charge transfer across CoS2/MoS2 heterointerface would induce the formation of local electrophilic/nucleophilic region, which will intelligently adsorb electron‐donating/electron‐withdrawing groups in urea molecule, activate the chemical bonds, and thus trigger the decomposition of urea. Benefiting from the regulation of local charge distribution, the constructed Schottky catalyst of CoS2‐MoS2 exhibits superior urea catalytic activities with a potential of 1.29 V (only 0.06 V higher than the thermodynamic voltage of water decomposition) to attain 10 mA cm−2 as well as robust durability over 60 h. This innovational manipulation of charge distribution via Schottky heterojunction provides a model in exploring other highly efficient electrocatalysts.

Commercial deployment of lithium anodes has been severely impeded by the poor battery safety, unsatisfying cycling lifespan, and efficiency. Recently, building artificial interfacial layers over a lithium anode was regarded as an effective strategy to stabilize the electrode. However, the fabrications reported so far have mostly been conducted directly upon lithium foil, often requiring stringent reaction conditions with indispensable inert environment protection and highly specialized reagents due to the high reactivity of metallic lithium. Besides, the uneven lithium‐ion flux across the lithium surface should be more powerfully tailored via mighty interfacial layer materials. Herein, g‐C3N4 is employed as a Li+‐modulating material and a brand‐new autotransferable strategy to fabricate this interfacial layer for Li anodes without any inert atmosphere protection and limitation of chemical regents is developed. The g‐C3N4 film is filtrated on the separator in air using a common alcohol solution and then perfectly autotransferred to the lithium surface by electrolyte wetting during normal cell assembly. The abundant nitrogen species within g‐C3N4 nanosheets can form transient LiN bonds to powerfully stabilize the lithium‐ion flux and thus enable a CE over 99% for 900 cycles and smooth deposition at high current densities and capacities, surpassing most previous works.

to exceptional mechanical flexibility within the layer and remarkable rigidity perpendicular to the layers. This anisotropic structural feature also conduces to effective chemical complexing. And attributed to the weak interlayer interactions, layer structured materials can readily be expanded, exfoliated, or self-assemble into various nanoarchitectures and the processes are always accompanied by the introduction of defects or phase transformation. [3] Therefore, layer structured materials show some unique application performances that nonlayer structured ones are hard to achieve. Specifically, the abilities of fast ion intercalation and charge transfer enable unparalleled high initial Coulombic efficiency, unexpected structure reversibility, and the formation of extra chemical bonds with other materials when used in alkali-metal ion batteries including lithium ion batteries (LIBs), sodium ion batteries (NIBs), and potassium ion batteries (KIBs). [4] The exfoliative feature induced high specific surface area, large amount of active sites as well as effective defect/strain/phase engineering also promise the feasibility to develop outstanding capacitor materials and efficient catalysts. Moreover, the superior mechanical flexibility and impressive energy storage capacity of layer structured materials could satisfy the requirement of the flexible devices. It is also feasible to develop new battery systems such as the aluminum or magnesium rechargeable batteries using the interlayer expansion approach. [5] With these unique properties, layer structured materials are expected to play more important roles in energy storage and conversion devices.However, the current available reviews involving layer structured materials are mostly based on their derivative 2D nanomaterials and the correlations between layer number and the final performances, [6] or focused much on synthetic methods, [3] advanced characterizations, [7] or centered on specific materials such as MoS 2 , [8] graphene, [9] transitional metal dichalcogenides (TMDs), [10] etc. In this review, great importance is attached to structural characteristics of layered materials and their unique performances induced by the inherent structural features when applied in energy storage and conversion. We start with a brief introduction of typical layered materials and their crystal structures, and then we summarize their structure endued exceptional properties. Afterwards, we highlight the layered structure Owing to the strong in-plane chemical bonds and weak van der Waals force between adjacent layers, investigations of layer structured materials have long been the hotspots in energy-related fields. The intrinsic large interlayer space endows them capabilities of guest ion intercalation, fast ion diffusion, and swift charge transfer along the channels. Meanwhile, the well-maintained in-plane integrity contributes to exceptional mechanical properties. This anisotropic structural feature is also conducive to effective chemical combination, exfoliation, or self-assembly in...

electrode kinetics, large volume change, and physical strains during the Li insertion/ extraction process, resulting in large polarization, rapidly declining capacity, and poor rate performances. [10] Moreover, it had been detected by various in situ techniques that serious irreversible transformation from crystallization to amorphous phase would occur for conversion type anodes along with their first discharge-charge process, which tends to lead poor initial coulombic efficiency (ICE) and fast capacity decay. [11] To better relax the structure stress during the charging/discharging, efforts have been made to synthesize the isotropic amorphous nanomaterials from the beginning to facilitate the stress relaxation and fruitful percolation pathway, which are proved effective to promote their cycle performance. [12] However, the low initial coulomb efficiency (usually <70%) and large voltage polarization are still unsolved due to the low conductivity of the electrode and poor electrochemical reversibility of the discharge product Li 2 O, which seriously impede the commercialization of such metal oxides anode materials. [13] Compared with the metal oxides, the typical layer structured metal sulfides or selenides MX 2 (M = Mo, W, X = S, Se) have attracted more and more research attention in recent years due to their unique structure properties and much better conductivity. [14] On the one hand, these metal sulfides possess superior structure flexibility due to their unique layered structure, which enables capabilities of quick Li ion intercalation, fast ion diffusion, and swift charge transfer along the interlayer space. [15] On the other hand, the conductivity of these sulfide or selenides (≈ ≥10 −4 S cm −1 ) is much higher than that of the metal oxides (≈ ≤10 −6 S cm −1 ) as well. [16] Moreover, metal sulfides show lower voltage as well as smaller charge/discharge voltage polarization than that of the metal oxides, promising a larger energy density and higher energy efficiency when assembled into the full cells. [17] However, similar to metal oxides, metal sulfide or selenides still suffer from serious structure destruction of their ordered layer characteristic, and the broken MX bonding along with lithiation process is hard to be rebuilt again even after Li + extraction. [10b,18] As a result, the electrode was mainly composed of metal M and S (Se) instead of original MX 2 after the first cycle, as reported in the typical cases of WS 2 and MoS 2 materials. [19] Therefore, low initial coulomb efficiency and The metal sulfide or selenides have attracted increasing attention for highenergy lithium-ion batteries due to their unique layer structure flexibility, higher conductivity, and lower voltage polarization than metal oxides. However, low initial coulomb efficiency (ICE), serious structure destruction, and irreversible bonding chemistry are still big challenges for their practical application. Herein, layer GeSe 2 and its carbon composite are synthesized by high-energy ball milling and it is surprisingly found that ...