Fluorinated Polyimide as a Novel High‐Voltage Binder for High‐Capacity Cathode of Lithium‐Ion Batteries

An increase in the energy density of lithium‐ion batteries has long been a competitive advantage for advanced wireless devices and long‐driving electric vehicles. Li‐rich layered oxide, xLi₂MnO₃?(1?x)LiMn_1?y?zNi_yCo_zO₂, is a promising high‐capacity cathode material for high‐energy batteries, whose capacity increases by increasing charge voltage to above 4.6 V versus Li. Li‐rich layered oxide cathode however suffers from a rapid capacity fade during the high‐voltage cycling because of instable cathode–electrolyte interface, and the occurrence of metal dissolution, particle cracking, and structural degradation, particularly, at elevated temperatures. Herein, this study reports the development of fluorinated polyimide as a novel high‐voltage binder, which mitigates the cathode degradation problems through superior binding ability to conventional polyvinylidenefluoride binder and the formation of robust surface structure at the cathode. A full‐cell consisting of fluorinated polyimide binder‐assisted Li‐rich layered oxide cathode and conventional electrolyte without any electrolyte additive exhibits significantly improved capacity retention to 89% at the 100th cycle and discharge capacity to 223–198 mA h g^?1 even under the harsh condition of 55 °C and high charge voltage of 4.7 V, in contrast to a rapid performance fade of the cathode coated with polyvinylidenefluoride binder.     

Faster Activation and Slower Capacity/Voltage Fading: A Bifunctional Urea Treatment on Lithium‐Rich Cathode Materials

Li‐rich layered oxides are promising cathode materials for next‐generation Li‐ion batteries because of their extraordinary specific capacity. However, the activation process of the key active component Li₂MnO₃ in Li‐rich materials is kinetically slow, and the complex phase transformation with electrode/electrolyte side reactions causes fast capacity/voltage fading. Herein, a simple thermal treatment strategy is reported to simultaneously tackle these challenges. The introduction of a urea thermal treatment on Li‐rich material Li_1.87Mn_0.94Ni_0.19O₃ leads to oxygen deficiencies and partially reduced Mn ions on the oxide surface for activating the Li‐rich phase. In situ synchrotron study confirms that the urea‐treated cathode shows much faster Li extraction from both Li and transition metal layers with less oxygen evolution upon charging than that of untreated counterparts. Moreover, the decomposition products of urea during thermal treatment subsequently deposit on the surface of cathode material, leading to a unique passivation layer against side reactions between electrode and electrolyte. Soft X‐ray absorption spectroscopy reveals the structural evolution mechanism with a significantly suppressed dissolution of Mn species over cycling measurement. The urea‐treated Li_1.87Mn_0.94Ni_0.19O₃ shows accelerated activation kinetics to reach high capacity of 270 mA h g^–1 and demonstrates excellent capacity retention of 98.49% over 300 cycles with slower voltage decay.     

Walnut‐Like Multicore–Shell MnO Encapsulated Nitrogen‐Rich Carbon Nanocapsules as Anode Material for Long‐Cycling and Soft‐Packed Lithium‐Ion Batteries

Metal oxide‐based nanomaterials are widely studied because of their high‐energy densities as anode materials in lithium‐ion batteries. However, the fast capacity degradation resulting from the large volume expansion upon lithiation hinders their practical application. In this work, the preparation of walnut‐like multicore–shell MnO encapsulated nitrogen‐rich carbon nanocapsules (MnO@NC) is reported via a facile and eco‐friendly process for long‐cycling Li‐ion batteries. In this hybrid structure, MnO nanoparticles are uniformly dispersed inside carbon nanoshells, which can simultaneously act as a conductive framework and also a protective buffer layer to restrain the volume variation. The MnO@NC nanocapsules show remarkable electrochemical performances for lithium‐ion batteries, exhibiting high reversible capability (762 mAh g^?1 at 100 mA g^?1) and stable cycling life (624 mAh g^?1 after 1000 cycles at 1000 mA g^?1). In addition, the soft‐packed full batteries based on MnO@NC nanocapsules anodes and commercial LiFePO₄ cathodes present good flexibility and cycling stability.     

Role of Ordered Ni Atoms in Li Layers for Li‐Rich Layered Cathode Materials

Li‐rich layered oxide materials are promising candidates for high‐energy Li‐ion batteries. They show high capacities of over 200 mAh g^?1 with the additional occupation of Li in their transition metal layers; however, the poor cycle performance induced by an irreversible phase transition limits their use in practical applications. In recent work, an atomic‐scale modified surface, in which Ni is ordered at 2c sites in the Li layers, significantly improves the performance in terms of reversible capacity and cycling stability. The role of the incorporated Ni on this performance, however, is not yet clearly understood. Here, the effects of the ordered Ni on Li battery performance are presented, based on first‐principles calculations and experimental observations. The Ni substitution suppresses the oxygen loss by moderating the oxidation of oxygen ions during the delithiation process and forms bonds with adjacent oxygen after the first deintercalation of Li ions. These Ni? O bonds contribute to the formation of a solid surface, resulting in the improved cycling stability. Moreover, the multivalent Ni suppresses Mn migration to the Li‐sites that causes the undesired phase transition. These findings from theoretical calculations and experimental observations provide insights to enhance the electrochemical performance of Li‐rich layered oxides.     

Drawing a Pencil‐Trace Cathode for a High‐Performance Polymer‐Based Li–CO2 Battery with Redox Mediator

Lithium–carbon dioxide (Li–CO₂) batteries have received wide attention due to their high theoretical energy density and CO₂ capture capability. However, this system still faces poor cycling performance and huge overpotential, which stems from the leakage/volatilization of liquid electrolyte and instability of the cathode. A gel polymer electrolyte (GPE)‐based Li–CO₂ battery by using a novel pencil‐trace cathode and 0.0025 mol L^?1 (M) binuclear cobalt phthalocyanine (Bi‐CoPc)‐containing GPE (Bi‐CoPc‐GPE) is developed here. The cathode, which is prepared by pencil drawing on carbon paper, is stable because of its typical limited‐layered graphitic structure without any binder. In addition, Bi‐CoPc‐GPE, which consists of polymer matrix filled with liquid electrolyte, exhibits excellent ion conductivity (0.86 mS cm^?1), effective protection for Li anode, and superior leakproof property. Moreover, Bi‐CoPc acts as a redox mediator to promote the decomposition of discharge products at low charge potential. Interestingly, different from polymer‐shaped discharge products formed in liquid electrolyte–based Li–CO₂ batteries, the morphology of products in Li–CO₂ batteries using Bi‐CoPc‐GPE is film‐like. Hence, this polymer‐based Li–CO₂ battery shows super‐high discharge capacity, low overpotential, and even steadily runs for 120 cycles. This study may pave a new way to develop high‐performance Li–CO₂ batteries.     

Nanoflake Arrays of Lithiophilic Metal Oxides for the Ultra‐Stable Anodes of Lithium‐Metal Batteries

A molten lithium infusion strategy has been proposed to prepare stable Li‐metal anodes to overcome the serious issues associated with dendrite formation and infinite volume change during cycling of lithium‐metal batteries. Stable host materials with superior wettability of molten Li are the prerequisite. Here, it is demonstrated that a series of strong oxidizing metal oxides, including MnO₂, Co₃O₄, and SnO₂, show superior lithiophilicity due to their high chemical reactivity with Li. Composite lithium‐metal anodes fabricated via melt infusion of lithium into graphene foams decorated by these metal oxide nanoflake arrays successfully control the formation and growth of Li dendrites and alleviate volume change during cycling. A resulting Li‐Mn/graphene composite anode demonstrates a super‐long and stable lifetime for repeated Li plating/stripping of 800 cycles at 1 mA cm^?2 without voltage fluctuation, which is eight times longer than the normal lifespan of a bare Li foil under the same conditions. Furthermore, excellent rate capability and cyclability are realized in full‐cell batteries with Li‐Mn/graphene composite anodes and LiCoO₂ cathodes. These results show a major advancement in developing a stable Li anode for lithium‐metal batteries.     

Tuning Anionic Redox Activity and Reversibility for a High‐Capacity Li‐Rich Mn‐Based Oxide Cathode via an Integrated Strategy

When fabricating Li‐rich layered oxide cathode materials, anionic redox chemistry plays a critical role in achieving a large specific capacity. Unfortunately, the release of lattice oxygen at the surface impedes the reversibility of the anionic redox reaction, which induces a large irreversible capacity loss, inferior thermal stability, and voltage decay. Therefore, methods for improving the anionic redox constitute a major challenge for the application of high‐energy‐density Li‐rich Mn‐based cathode materials. Herein, to enhance the oxygen redox activity and reversibility in Co‐free Li‐rich Mn‐based Li_1.2Mn_0.6Ni_0.2O₂ cathode materials by using an integrated strategy of Li₂SnO₃ coating‐induced Sn doping and spinel phase formation during synchronous lithiation is proposed. As an Li⁺ conductor, a Li₂SnO₃ nanocoating layer protects the lattice oxygen from exposure at the surface, thereby avoiding irreversible oxidation. The synergy of the formed spinel phase and Sn dopant not only improves the anionic redox activity, reversibility, and Li⁺ migration rate but also decreases Li/Ni mixing. The 1% Li₂SnO₃‐coated Li_1.2Mn_0.6Ni_0.2O₂ delivers a capacity of more than 300 mAh g^?1 with 92% Coulombic efficiency. Moreover, improved thermal stability and voltage retention are also observed. This synergic strategy may provide insights for understanding and designing new high‐performance materials with enhanced reversible anionic redox and stabilized surface lattice oxygen.     

Highly Surface‐Wrinkled and N‐Doped CNTs Anchored on Metal Wire: A Novel Fiber‐Shaped Cathode toward High‐Performance Flexible Li–CO2 Batteries

Li–CO₂ batteries are regarded as a promising candidate for the next‐generation high‐performance electrochemical energy storage system owing to their ultrahigh theoretical energy density and environmentally friendly CO₂ fixation ability. Until now, the majority of reported catalysts for Li–CO₂ batteries are in the powder state. Thus, the air electrodes are produced in 2D rigid bulk structure and their electrochemical properties are negatively influenced by binder. The nondeformable feature and unsatisfactory performance of the cathode have already become the main obstacles that hinder Li–CO₂ batteries toward ubiquity for wearable electronics. In this work, for the first time, a flexible hybrid fiber is reported comprising highly surface‐wrinkled and N‐doped carbon nanotube (CNT) networks anchored on metal wire as the cathode integrated with high performance and high flexibility for fiber‐shaped Li–CO₂ battery. It exhibits a large discharge capacity as high as 9292.3 mAh g^?1, an improved cycling performance of 45 cycles, and a decent rate capability. A quasi‐solid‐state flexible fiber‐shaped Li–CO₂ battery is constructed to illustrate the advantages on mechanical flexibility of this fiber‐shaped cathode. Experiments and theoretical simulations prove that those doped pyridinic nitrogen atoms play a critical role in facilitating the kinetics of CO₂ reduction and evolution reaction, thereby enabling distinctly enhanced electrochemical performance.     

Dendrimer‐Encapsulated Ruthenium Oxide Nanoparticles as Catalysts in Lithium‐Oxygen Batteries

Dendrimer‐encapsulated ruthenium oxide nanoparticles (DEN‐RuO₂) have been used as catalysts in lithium‐oxygen (Li‐O₂) batteries for the first time. The results obtained from ultraviolet‐visible spectroscopy, electron microscopy and X‐ray photoelectron spectroscopy show that the nanoparticles synthesized by the dendrimer template method are ruthenium oxide, not metallic ruthenium as reported by other groups. The DEN‐RuO₂ significantly improves the cycling stability of Li‐O₂ batteries with carbon electrodes and decreases the charging potential even at ten times less catalyst loading than those reported previously. The monodispersity, porosity, and large number of surface functionalities of the dendrimer template prevent the aggregation of the RuO₂ nanoparticles, making their entire surface area available for catalysis. The potential of using DEN‐RuO₂ as a standalone cathode material for Li‐O₂ batteries is also explored.     

Iron Fluoride–Carbon Nanocomposite Nanofibers as Free‐Standing Cathodes for High‐Energy Lithium Batteries

The development of low‐cost, high‐energy cathodes from nontoxic, broadly available resources is a big challenge for the next‐generation rechargeable lithium or lithium‐ion batteries. As a promising alternative to traditional intercalation‐type chemistries, conversion‐type metal fluorides offer much higher theoretical capacity and energy density than conventional cathodes. Unfortunately, these still suffer from irreversible structural degradation and rapid capacity fading upon cycling. To address these challenges, here a versatile and effective strategy is harnessed for the development of metal fluoride–carbon (C) nanocomposite nanofibers as flexible, free‐standing cathodes. By taking iron trifluoride (FeF₃) as a successful example, assembled FeF₃–C/Li cells with a high reversible FeF₃ capacity of 550 mAh g^?1 at 100 mA g^?1 (three times that of traditional cathodes, such as lithium cobalt oxide, lithium nickel cobalt aluminum oxide, and lithium nickel cobalt manganese oxide) and excellent stability (400+ cycles with little‐to‐no degradation) are demonstrated. The promising characteristics can be attributed to the nanoconfinement of FeF₃ nanoparticles, which minimizes the segregation of Fe and LiF upon cycling, the robustness of the electrically conductive C network and the prevention of undesirable reactions between the active material and the liquid electrolyte using the composite design and electrolyte selection.     

Graphene Oxide Gel‐Derived,Free‐Standing,Hierarchically Porous Carbon for High‐Capacity and High‐Rate Rechargeable Li‐O2 Batteries

Lithium‐oxygen (Li‐O₂) batteries are one of the most promising candidates for high‐energy‐density storage systems. However, the low utilization of porous carbon and the inefficient transport of reactants in the cathode limit terribly the practical capacity and, in particular, the rate capability of state‐of‐the‐art Li‐O₂ batteries. Here, free‐standing, hierarchically porous carbon (FHPC) derived from graphene oxide (GO) gel in nickel foam without any additional binder is synthesized by a facile and effective in situ sol‐gel method, wherein the GO not only acts as a special carbon source, but also provides the framework of a 3D gel; more importantly, the proper acidity via its intrinsic COOH groups guarantees the formation of the whole structure. Interestingly, when employed as a cathode for Li‐O₂ batteries, the capacity reaches 11 060 mA h g^?1 at a current density of 0.2 mA cm^?2 (280 mA g^?1); and, unexpectedly, a high capacity of 2020 mA h g^?1 can be obtained even the current density increases ten times, up to 2 mA cm^?2 (2.8 A g^?1), which is the best rate performance for Li‐O₂ batteries reported to date. This excellent performance is attributed to the synergistic effect of the loose packing of the carbon, the hierarchical porous structure, and the high electronic conductivity of the Ni foam.     

3D Porous Cu Current Collector/Li‐Metal Composite Anode for Stable Lithium‐Metal Batteries

Lithium‐metal batteries are of particular interest for next‐generation electrical energy storage because of their high energy density on both volumetric and gravimetric bases. Effective strategies to stabilize the Li‐metal anode are the prerequisite for the progress of these exceptional storage technologies, such as Li–S and Li–O₂ batteries. Various challenges, such as uneven Li electrodeposition, anode volume expansion, and dendrite‐induced short‐circuit have hindered the practical application of rechargeable Li‐metal batteries. Herein, a one‐step facile and cost‐effective strategy for stabilizing lithium‐metal batteries via 3D porous Cu current collector/Li‐metal composite anode is reported. The porous structure of the composite electrode provides a “cage” for the redeposition of “hostless” lithium and accommodates the anode volume expansion during cycling. Compared with planar Cu foil, its high specific surface area favors the electrochemical reaction kinetics and lowers the local current density along the anode. It leads to low interfacial resistance and stabilizes the Li electrodeposition. On this basis, galvanostatic measurements are performed on both symmetric cells and Li/Li₄Ti₅O₁₂ cells and it is found that the electrodes exhibit exceptional abilities of promoting cell lifetime and stabilizing the cycling behavior. Although this work focuses on lithium metal, this novel tactic is easy to generalize to other metal electrodes.     

A LiF Nanoparticle‐Modified Graphene Electrode for High‐Power and High‐Energy Lithium Ion Batteries

Surface modification of carbon materials plays an important role in tailoring carbon surface chemistry to specify their electrochemical performance. Here, a surface modification strategy for graphene is proposed to produce LiF‐nanoparticle‐modified graphene as a high‐rate, large‐capacity pre‐lithiated electrode for high‐power and high‐energy lithium ion batteries. The LiF nanoparticles covering the active sites of the graphene surface provide an extra Li source and act as an effective solid electrolyte interphase (SEI) inhibiter to suppress LiFP₆ electrolyte decomposition reactions, affect SEI components, and reduce their thickness. Consequently, the Li‐ion diffusion is greatly sped up and the thermodynamic stability of the electrode is significantly improved. This modified graphene electrode shows excellent rate capability and improved first‐cycle coulombic efficiency, cycling stability, and ultrahigh power and energy densities accessible during fast charge/discharge processes.     

Manipulating the Electronic Structure of Li‐Rich Manganese‐Based Oxide Using Polyanions: Towards Better Electrochemical Performance

Lithium‐rich manganese‐based layered oxides show great potential as high‐capacity cathode materials for lithium ion batteries, but usually exhibit a poor cycle life, gradual voltage drop during cycling, and low thermal stability in the highly delithiated state. Herein, a strategy to promote the electrochemical performance of this material by manipulating the electronic structure through incorporation of boracic polyanions is developed. As‐prepared Li[Li_0.2Ni_0.13Co_0.13Mn_0.54](BO₄)_0.015(BO₃)_0.005O_1.925 shows a decreased M‐O covalency and a lowered O 2p band top compared with pristine Li[Li_0.2Ni_0.13Co_0.13Mn_0.54]O₂. As a result, the modified cathode exhibits a superior reversible capacity of 300 mA h g^?1 after 80 cycles, excellent cycling stability with a capacity retention of 89% within 300 cycles, higher thermal stability, and enhanced redox couple potentials. The improvements are correlated to the enhanced oxygen stability that originates from the tuned electronic structure. This facile strategy may further be extended to other high capacity electrode systems.     

Surface Structural Transition Induced by Gradient Polyanion‐Doping in Li‐Rich Layered Oxides: Implications for Enhanced Electrochemical Performance

Lithium‐rich layered oxides (LLOs) exhibit great potential as high‐capacity cathode materials for lithium‐ion batteries, but usually suffer from capacity/voltage fade during electrochemical cycling. Herein, a gradient polyanion‐doping strategy is developed to initiate surface structural transition to form a spinel‐like surface nanolayer and a polyanion‐doped layered core material in LLOs simultaneously. This strategy integrates the advantages of both bulk doping and surface modification as the oxygen close‐packed structure of LLOs is stabilized by polyanion doping, and the LLO cathodes are protected from steady corrosion induced by electrolytes. A LLO material modified with 5 at% phosphate (5%P@LLO) shows a high reversible discharge capacity of ≈300 mAh g^?1 at 0.1 C, excellent cycling stability with a capacity retention of 95% after 100 cycles, and enhanced electrode kinetics. This gradient doping strategy can be further extended to other polyanion‐doped LLO materials, such as borate and silicate polyanions.     

Liquid Polydimethylsiloxane Grafting to Enable Dendrite‐Free Li Plating for Highly Reversible Li‐Metal Batteries

Li‐metal is considered as the most promising anode material to advance the development of next‐generation energy storage devices owing to its unparalleled theoretical specific capacity and extremely low redox electrochemical potential. However, safety concerns and poor cycling retention of Li‐metal batteries (LMBs) caused by uncontrolled Li dendrite growth still limit their broad application. Herein, liquid polydimethylsiloxane (PDMS) terminated by –OCH₃ groups is proposed as a graftable additive to reinforce the anode dendrite suppression for LMBs. Such a grafting triggers the formation of a conformal hybrid solid electrolyte interphase (SEI) with increased fractions of LiF and Li–Si–O‐based moieties, which serve as a rigid barrier and ionic conductor for uniform Li‐ion flow and Li‐mass deposition. The grafting protected anode endows Li/Li symmetric cells with a long lifetime over 1800 h with a much smaller voltage gap (≈25 mV) between Li plating and stripping, than the naked anode. The coulombic efficiency values for Li/Cu asymmetric cells in carbonate electrolyte can reach up to 97% even at a high current density of 3 mA cm^?2 or high capacity up to 4 mAh cm^?2. The liquid PDMS additive shows advantage over solid siloxane additives with poor grafting ability in terms of Li surface compaction and SEI stabilization.     

Adiponitrile (C6H8N2): A New Bi‐Functional Additive for High‐Performance Li‐Metal Batteries

Rechargeable batteries with a Li metal anode and Ni‐rich Li[Ni_xCo_yMn_1?x?y]O₂ cathode (Li/Ni‐rich NCM battery) have been emerging as promising energy storage devices because of their high‐energy density. However, Li/Ni‐rich NCM batteries have been plagued by the issue of the thermodynamic instability of the Li metal anode and aggressive surface chemistry of the Ni‐rich cathode against electrolyte solution. In this study, a bi‐functional additive, adiponitrile (C₆H₈N₂), is proposed which can effectively stabilize both the Li metal anode and Ni‐rich NCM cathode interfaces. In the Li/Ni‐rich NCM battery, the addition of 1 wt% adiponitrile in 0.8 m LiTFSI + 0.2 M LiDFOB + 0.05 M LiPF₆ dissolved in EMC/FEC = 3:1 electrolyte helps to produce a conductive and robust Li anode/electrolyte interface, while strong coordination between Ni⁴⁺ on the delithiated Ni‐rich cathode and nitrile group in adiponitrile reduces parasitic reactions between the electrolyte and Ni‐rich cathode surface. Therefore, upon using 1 wt% adiponitrile, the Li/full concentration gradient Li[Ni_0.73Co_0.10Mn_0.15Al_0.02]O₂ battery achieves an unprecedented cycle retention of 75% over 830 cycles under high‐capacity loading of 1.8 mAh cm^?2 and fast charge–discharge time of 2 h. This work marks an important step in the development of high‐performance Li/Ni‐rich NCM batteries with efficient electrolyte additives.     

Elastic Carbon Nanotube Aerogel Meets Tellurium Nanowires: A Binder‐ and Collector‐Free Electrode for Li‐Te Batteries

Rechargeable Li batteries based on group VIA element cathodes, such as tellurium, are emerging due to their capability to provide equivalent theoretical volumetric capacity density to O and S, as well as an improved activity to react with Li. Herein, bifunctional and elastic carbon nanotube (CNT) aerogel is fabricated to combine with Te nanowires, yielding two types of binder/collector‐free Te cathodes to assemble Li‐Te batteries. The CNTs with high electronic conductivity and hollow porous structure enable stable electric contact and fast transportation of Li⁺, while trapping Te and Li₂Te in its network, triggering fast and stable Li‐Te electrochemistry. Both cathodes are also provided with fine compressibility, helping to buffer their volume changes during lithiation/delithiation and improving electrode integrity. Both cathodes deliver high specific capacity, fine cycling stability, and favorable high‐rate capability, proving their competence in building high‐energy rechargeable Li‐ion batteries.     

3D Carbonaceous Current Collectors: The Origin of Enhanced Cycling Stability for High‐Sulfur‐Loading Lithium–Sulfur Batteries

The cycling stability of high‐sulfur‐loading lithium–sulfur (Li–S) batteries remains a great challenge owing to the exaggerated shuttle problem and interface instability. Despite enormous efforts on design of advanced electrodes and electrolytes, the stability issue raised from current collectors has been rarely concerned. This study demonstrates that rationally designing a 3D carbonaceous macroporous current collector is an efficient and effective “two‐in‐one” strategy to improve the cycling stability of high‐sulfur‐loading Li–S batteries, which is highly versatile to enable various composite cathodes with sulfur loading >3.7 mAh cm^?2. The best cycling performance can be achieved upon 950 cycles with a very low decay rate of 0.029%. Moreover, the origin of such a huge enhancement in cycling stability is ascribed to (1) the inhibition of electrochemical corrosion, which severely occurs on the typical Al foil and disables its long‐term sustainability for charge transfer, and (2) the passivation of cathode surface. The role of the chemical resistivity against corrosion and favorable macroscopic porous structure is highlighted for exploiting novel current collectors toward exceptional cycling stability of high‐sulfur‐loading Li–S batteries.     

A Composite of Carbon‐Wrapped Mo2C Nanoparticle and Carbon Nanotube Formed Directly on Ni Foam as a High‐Performance Binder‐Free Cathode for Li‐O2 Batteries

Cathode design is indispensable for building Li‐O₂ batteries with long cycle life. A composite of carbon‐wrapped Mo₂C nanoparticles and carbon nanotubes is prepared on Ni foam by direct hydrolysis and carbonization of a gel composed of ammonium heptamolybdate tetrahydrate and hydroquinone resin. The Mo₂C nanoparticles with well‐controlled particle size act as a highly active oxygen reduction reactions/oxygen evolution reactions (ORR/OER) catalyst. The carbon coating can prevent the aggregation of the Mo₂C nanoparticles. The even distribution of Mo₂C nanoparticles results in the homogenous formation of discharge products. The skeleton of porous carbon with carbon nanotubes protrudes from the composite, resulting in extra voids when applied as a cathode for Li‐O₂ batteries. The batteries deliver a high discharge capacity of ≈10 400 mAh g^?1 and a low average charge voltage of ≈4.0 V at 200 mA g^?1. With a cutoff capacity of 1000 mAh g^?1, the Li‐O₂ batteries exhibit excellent charge–discharge cycling stability for over 300 cycles. The average potential polarization of discharge/charge gaps is only ≈0.9 V, demonstrating the high ORR and OER activities of these Mo₂C nanoparticles. The excellent cycling stability and low potential polarization provide new insights into the design of highly reversible and efficient cathode materials for Li‐O₂ batteries.