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All-carbon graphdiyne (GDY)-based materials have attracted extensive attention owing to their extraordinary structures and outstanding performance in electrochemical energy storage. Straightforward insights into the interfacial evolution at GDY electrode/electrolyte interface could crucially enrich the fundamental comprehensions and inspire targeted regulations. Herein

Lithium-sulfur batteries (LSBs) suffer from sluggish reaction kinetics of sulfur-containing species and loss of soluble polysulfides (PSs) during cycling, especially in the case of liquid electrolytes. Here, we improve the kinetics of sulfur species by decorating Mo2C nanoparticles on carbon nanotubes (CNTs) as the host for sulfur active mass. In addition, by use of gel polymer electrolytes (GPEs) derived from in situ polymerization of 1,3-dioxolane (DOL) to mitigate the diffusion of PSs and improve the stability of Li stripping/plating. As a result, the sulfur cathodes are endowed with enhanced initial specific capacity and suppressed dissolution of sulfur species. The cells with CNT/Mo2C/S cathodes and GPE exhibit excellent electrochemical performance. The anodes cycled with GPE show remarkably enhanced lithium plating-stripping behavior. Benefitting from the synergistic effect, LSBs with higher energy density and improved durability are obtained, demonstrating a new approach for developing high-performance quasi-solid-state Li metal batteries.

Composite electrolytes composed of a nanoceramic and polymer have been widely studied because of their high ionic conductivity, good Li-ion transference number, and excellent machinability, whereas the intrinsic reason for the improvement of performance is ambiguous. Herein, we have designed a functional polymer skeleton with different types of nanofiller to reveal the superiority of fast ion conductors in composite electrolyte. Three types of ceramics with different dielectric constants and Li-ion transfer ability were selected to prepare composite electrolytes, the composition, structure, and electrochemical performances of which were systematically investigated. It was found that the addition of fast ion conductive ceramics could provide a high Li-ion transference ability and decreased diffusion barrier because the additional pathways existed in the ceramic, which are revealed by experiment and density functional theory calculations. Benefiting from the superiority of fast ion conductor, Li-metal batteries with this advanced composite electrolyte exhibit an impressive cycling stability and enable a dendrite-free Li surface after cycling. Our work enriches the understanding of the function of fast ion conductors in composite electrolyte and guides the design for other high-performance composite electrolytes in rechargeable solid batteries.

Li+-conductive ceramic oxide electrolytes, such as garnet-structured Li7La3Zr2O12, have been considered as promising candidates for realizing the next-generation solid-state Li-metal batteries with high energy density. Practically, the ceramic pellets sintered at elevated temperatures are often provided with high stiffness yet low fracture toughness, making them too brittle for the manufacture of thin-film electrolytes and strain-involved operation of solid-state batteries. The ceramic powder, though provided with ductility, does not yield satisfactorily high Li+ conductivity due to poor ion conduction at the boundaries of ceramic particles. Here we show, with solid-state nuclear magnetic resonance, that a uniform conjugated polymer nanocoating formed on the surface of ceramic oxide particles builds pathways for Li+ conduction between adjacent particles in the unsintered ceramics. A tape-casted thin-film electrolyte (thickness

Two-dimensional layered transition-metal dichalcogenides (TMDs) have attracted intense interest for their layer number-dependent electronic properties and have exciting potential for atomically thi...

Lithium (Li) metal is one of the most promising anodes for the high-energy density lithium batteries. Nevertheless, it is still a great challenge to construct a dendrite-free Li anode with stable solid electrolyte interphase (SEI) by adopting environmentally friendly approaches. Herein, a green artificial Li polylactic acid (LiPLA) SEI layer with biodegradability and highly rebound resilience is fabricated via an in situ reaction to regulate Li metal plating/stripping behavior. Guided by this stable environmentally friendly LiPLA SEI, the Li anode shows excellent stability with suppressive dendrites as demonstrated by a stable cycling of 850 h in LiPLA-Li/LiPLA-Li symmetric batteries and a significant capacity retention rate enhancement of 18% in LiPLA-Li/LiFePO4 full batteries and 25% in LiPLA-Li/LiNi3/5Co1/5-Mn1/5O2 full batteries. This proposed strategy provides a green and facile way to ameliorate the stability of the Li anode for safe and long-life lithium metal batteries.

Constructing advanced anode materials with suitable operational potential and high energy density toward metal ion batteries is of significance for next-generation batteries. Carbon-coated porous Sb2Te3 nanoplates with high density and suitable operational potential, prepared by a hydrothermal and carbonization technique, manifest good electrochemical performance, including excellent rate capability, high capacities, and outstanding cycling performance. This performance can be traced to its special structure, including porous Sb2Te3 and the shell of carbon, which can provide fast charge transfer paths and maintain the structural stability for the entire material. The proposed strategy here of embedding porous high-density anode material in two-dimensional carbon provides a new avenue for designing anode materials with excellent gravimetric and volumetric capacities toward superior energy storage.

Sodium batteries have been regarded as promising candidates for large-scale energy storage application, provided cathode hosts with high energy density and long cycle life can be found. Herein, we report NASICON-structured Na3MnZr(PO4)3 as a cathode for sodium batteries that exhibits an electrochemical performance superior to those of other manganese phosphate cathodes reported in the literature. Both the Mn4+/Mn3+ and Mn3+/Mn2+ redox couples are reversibly accessed in Na3MnZr(PO4)3, providing high discharge voltage plateaus at 4.0 and 3.5 V, respectively. A high discharge capacity of 105 mAh g-1 was obtained from Na3MnZr(PO4)3 with a small variation of lattice parameters and a small volume change on extraction of two Na+ ions per formula unit. Moreover, Na3MnZr(PO4)3 exhibits an excellent cycling stability, retaining 91% of the initial capacity after 500 charge/discharge cycles at 0.5 C rate. On the basis of structural analysis and density functional theory calculations, we have proposed a detailed desodiation pathway from Na3MnZr(PO4)3 where Mn and Zr are disordered within the structure. We further show that the cooperative Jahn-Teller distortion of Mn3+ is suppressed in the cathode and that Na2MnZr(PO4)3 is a stable phase.

Lithium carbonate on the surface of garnet blocks Li+ conduction and causes a huge interfacial resistance between the garnet and electrode. To solve this problem, this study presents an effective strategy to reduce significantly the interfacial resistance by replacing Li2CO3 with Li ion conducting Li3N. Compared to the surface Li2CO3 on garnet, Li3N is not only a good Li+ conductor but also offers a good wettability with both the garnet surface and a lithium metal anode. In addition, the introduction of a Li3N layer not only enables a stable contact between the Li anode and garnet electrolyte but also prevents the direct reduction of garnet by Li metal over a long cycle life. As a result, a symmetric lithium cell with this Li3N-modified garnet exhibits an ultralow overpotential and stable plating/stripping cyclability without lithium dendrite growth at room temperature. Moreover, an all-solid-state Li/LiFePO4 battery with a Li3N-modified garnet also displays high cycling efficiency and stability over 300 cycles even at a temperature of 40 °C.

A novel covalent organic framework polymer material that bears conjugated anthraquinone and triazine units in its skeleton has been prepared via a facile one-pot condensation reaction and employed as an anode material for Li-ion batteries. The conjugated units consist of C═N groups, C═O groups, and benzene groups, which enable a 17-electron redox reaction with Li per repeating unit and bring a theoretical specific capacity of 1450 mA h g-1. The polymer also shows a large specific surface area and a hierarchically porous structure to trigger interfacial Li storage and contribute to an additional capacity. The highly conductive conjugated polymer skeleton enables fast electron transport to facilitate the Li storage. In this way, the polymer electrode shows a large specific capacity and favorable cycling and rate performance, making it an appealing anode choice for the next-generation high-energy batteries.

A selective CO evolution from photoreduction of CO2 in water was achieved on a noble-metal-free, carbide-based composite catalyst, as demonstrated by a CO selectivity of 98.3% among all carbon-containing products and a CO evolution rate of 29.2 μmol h–1, showing superiority to noble-metal-based catalyst. A rapid separation of the photogenerated electron–hole pairs and improved CO2 adsorption on the surface of the carbide component are responsible for the excellent performance of the catalyst. The high CO selectivity is accompanied by a predominant H2 evolution, which is believed to provide a proton-deficient environment around the catalyst to favor the formation of hydrogen-deficient carbon products. The present work provides general insights into the design of a catalyst with a high product selectivity and also the carbon evolution chemistry during a photocatalytic reaction.

In this work, nitrogen-doped LaNiO3 perovskite was prepared and studied, for the first time, as a bifunctional electrocatalyst for oxygen cathode in a rechargeable lithium–oxygen battery. N doping was found to significantly increase the Ni3+ contents and oxygen vacancies on the bulk surface of the perovskite, which helped to promote the oxygen reduction reaction and oxygen evolution reaction of the cathode and, therefore, enabled reversible Li2O2 formation and decomposition on the cathode surface. As a result, the oxygen cathodes loaded with N-doped LaNiO3 catalyst showed an improved electrochemical performance in terms of discharge capacity and cycling stability to promise practical Li–O2 batteries.

Retaining soluble polysulfides in the sulfur cathodes and allowing for deep redox are essential to develop high-performance lithium–sulfur batteries. The versatile textures and physicochemical characteristics of abundant biomass offer a great opportunity to prepare biochar materials that can enhance the performance of Li–S batteries in sustainable mode. Here, we exploit micro-/mesoporous coconut shell carbon (CSC) with high specific surface areas as a sulfur host for Li–S batteries. The sulfur-infiltrated CSC materials show superior discharge–charge capacity, cycling stability, and high rate capability. High discharge capacities of 1599 and 1500 mA h g–1 were achieved at current rates of 0.5 and 2.0 C, respectively. A high reversible capacity of 517 mA h g–1 was retained at 2.0 C even after 400 cycles. The results demonstrate a high retention and a deep lithiation of the CSC-confined sulfur. The success of this strategy provides insights into seeking high-performance biochar materials for Li–S batteries f...

Aluminum has long been regarded as a promising anode for energy storage because of its high energy density and low cost, but its application is hindered by the inability of cathodes to provide reversible Al3+ insertion. In contrast, we show how the use of Al as cathode enables a rechargeable high-energy battery. The battery comprises a molten sodium anolyte and a molten NaAl2Cl7 catholyte, separated by a NaSICON solid Na+ electrolyte. It is operated at 200 °C to overcome the ceramic separator kinetics and to keep sodium and NaAl2Cl7 in the molten state. Because of the simple composition and trivalence of Al, the sodium anolyte and NaAl2Cl7 catholyte together show a high energy density of 366 Wh kg–1, although its voltage is only about 1.55 V and only 60% of the capacity can be realized. The high energy density, low-cost, and internal safety make this new cell chemistry applicable to the large-scale energy storage market.

Driven by an increasing demand on storage devices with higher energy outputs and better safety, solid-state lithium metal batteries have shown their potential to replace the traditional liquid-based Li-ion batteries and power the future storage market. In this Perspective, we will show our views on improving this emerging battery system by nanoscience. Discussions will be placed, from both scientific and engineering points of view, on the fundamentals and problems of the battery and its key components. The corresponding “nano” strategies will also be addressed, as well as recent progress in related fields including materials synthesis, battery design, and characterization techniques. With these efforts, we want to provide insights on rational design of the solid-state Li metal battery for optimized performance.

Developing efficient noble-metal-free catalysts for photocatalysis under the irradiation of visible light, which is the main part of sunlight (44%), would represent a significant step toward making photocatalysis a more competitive strategy for solar energy utilization. Herein, nanospheres (∼200 nm) containing dimolybdenum carbide and carbon (Mo2C@C) were used to support CdS nanoparticles (∼5 nm) to form a noble-metal-free CdS/Mo2C@C photocatalyst. CdS/Mo2C@C shows an enhanced visible-light-driven photocatalytic H2 evolution from water, with a H2 evolution rate of 554.3 μmol h–1, which is about 2 times higher than that on the widely used noble-metal-based CdS/Pt photocatalyst. Improved absorption of the visible light and separation of the photogenerated electron–hole pairs could be the origins for the enhanced photocatalytic activity of CdS/Mo2C@C. The findings of this work will open a new door for fabricating efficient noble-metal-free photocatalysts for visible-light-driven photocatalysis.

Lithium metal is a promising battery anode. However, inhomogeneous mass and charge transfers across the Li/electrolyte interface result in formation of dendritic Li and “dead” Li, and an unstable solid electrolyte interphase, which incur serious problems to impede its service in rechargeable batteries. Here, we show that the above problems can be mitigated by regulating the interfacial mass/charge transfer. The key to our strategy is hybrid Li storage in onion-like, graphitized spherical C granules wired on a three-dimensional conducting skeleton, which enhances the negativity of surface charge of the C host to contribute to a uniform Li plating while also forming stable Li/C intercalation compounds to offset any irreversible Li loss during cycling. As a result, the anode shows a suppressed dendrite formation and a high Li utilization >95%, enabling a practical Li battery to strike a long lifespan of 1000 cycles at a surplus Li of merely 5%.

A well-organized selenium/carbon nanosheets nanocomposite(Se/CNSs) is prepared by confining chain-like Sen molecules in hierarchically micromesoporous carbon nanosheets. A unique two-dimensional morphology and high graphitization degree of carbon nanosheets benefits fast Li+/e– access to the active Se, which guarantees a high utilization of Se during the(de)lithiation process. Besides, the chain-like Se molecules confined in the carbon matrix could alleviate the shuttle effect of polyselenides and promise a stable electrochemistry. Therefore, the resultant Se/CNSs delivers a highly reversible capacity, a long cycle life and favorable rate capabilities. Furthermore, a Li–Se pouch cell built from a metallic Li anode and the as-prepared Se/CNSs cathode exhibits an excellent electrochemical performance, demonstrating the potential of Se/CNSs in serving future energy storage devices with high energy density.

The practical use of lithium-sulfur batteries for the next-generation energy storage, especially the automobiles, was hindered by low electronic conductivity of sulfur and the resulting poor rate capabilities. Here, we report a sulfur-carbon composite by confining S into a graphene sandwiched in mesoporous carbon nanosheets with a two-dimensional ultrathin morphology, suitable mesopore size and large pore volume, and excellent electronic conductivity. Serving as cathode material for a Li-S battery, the elaborately designed S/C composite leads to "kinetically stable" transmissions of Li ions and electrons, triggering a stable electrochemistry and a record-breaking rate performance. In this way, the S/C composite has been proved a promising cathode material for high-rate Li-S batteries targeted at automobile storage.

NASICON (Na+ super ionic conductor) structures of NaxMV(PO4)3 (M = Mn, Fe, Ni) were prepared, characterized by aberration-corrected STEM and synchrotron radiation, and demonstrated to be durable cathode materials for rechargeable sodium-ion batteries. In Na4MnV(PO4)3, two redox couples of Mn3+/Mn2+ and V4+/V3+ are accessed with two voltage plateaus located at 3.6 and 3.3 V and a capacity of 101 mAh g–1 at 1 C. Furthermore, the Na4MnV(PO4)3 cathode delivers a high initial efficiency of 97%, long durability over 1000 cycles, and good rate performance to 10 C. The robust framework structure and stable electrochemical performance makes it a reliable cathode materials for sodium-ion batteries.

Hard carbons attract myriad interest as anode materials for high-energy rechargeable batteries due to their low costs and high theoretical capacities; practically, they deliver unsatisfactory performance due to their intrinsically disordered microarchitecture. Here we report a facile ion-catalyzed synthesis of a phenol–formaldehyde resin-based hard-carbon aerogel that takes advantage of the chelation effect of phenol and Fe3+, which consists of a three-dimensionally interconnected carbon network embedded with hydrogen-rich, ordered microstructures of expanded nanographites and carbon micropores. The chelation effect ensures the homodispersion of Fe in the polymer segments of the precursor, so that an effective catalytic conversion from sp3 to sp2 carbon occurs, enabling free rearrangement of graphene sheets into expanded nanographite and carbon micropores. The structural merits of the carbon offer chances to achieve lithium/sodium storage performance far beyond that possible with the conventional carbon a...

Substitution of selenium for sulfur in the cathode of a rechargeable battery containing Sx molecules in microporous slits in carbon allows a better characterization of the electrochemical reactions that occur. Paired with a metallic lithium anode, the Sex chains are converted to Li2Se in a single-step reaction. With a sodium anode, a sequential chemical reaction is characterized by a continuous chain shortening of Sex upon initial discharge before completing the reduction to Na2Se; on charge, the reconstituted Sex molecules retain a smaller x value than the original Sex chain molecule. In both cases, the Se molecules remain almost completely confined to the micropore slits to give a long cycle life.

In this work, Ni-doped manganite perovskite oxides (La0.8Sr0.2Mn(1-x)Ni(x)O3, x = 0.2 and 0.4) and undoped La0.8Sr0.2MnO3 were synthesized via a general and facile sol-gel route and used as bifunctional catalysts for oxygen cathode in rechargeable lithium-air batteries. The structural and compositional characterization results showed that the obtained La0.8Sr0.2Mn(1-x)Ni(x)O3 (x = 0.2 and 0.4) contained more oxygen vacancies than did the undoped La0.8Sr0.2MnO3 as well as a certain amount of Ni(3+) (eg = 1) on their surface. The Ni-doped La0.8Sr0.2Mn(1-x)Ni(x)O3 (x = 0.2 and 0.4) was provided with higher bifunctional catalytic activities than that of the undoped La0.8Sr0.2MnO3. In particular, the La0.8Sr0.2Mn0.6Ni0.4O3 had a lower total over potential between the oxygen evolution reaction and the oxygen reduction reaction than that of the La0.8Sr0.2MnO3, and the value is even comparable to that of the commercial Pt/C yet is provided with a much reduced cost. In the lithium-air battery, oxygen cathodes containing the La0.8Sr0.2Mn0.6Ni0.4O3 catalyst delivered the optimized electrochemical performance in terms of specific capacity and cycle life, and a reasonable reaction mechanism was given to explain the improved performance.

Carbon is one of the essential elements in energy storage. In rechargeable lithium batteries, researchers have considered many types of nanostructured carbons, such as carbon nanoparticles, carbon nanotubes, graphene, and nanoporous carbon, as anode materials and, especially, as key components for building advanced composite electrode materials. Nanocarbons can form efficient three-dimensional conducting networks that improve the performance of electrode materials suffering from the limited kinetics of lithium storage. Although the porous structure guarantees a fast migration of Li ions, the nanocarbon network can serve as an effective matrix for dispersing the active materials to prevent them from agglomerating. The nanocarbon network also affords an efficient electron pathway to provide better electrical contacts. Because of their structural stability and flexibility, nanocarbon networks can alleviate the stress and volume changes that occur in active materials during the Li insertion/extraction process. Through the elegant design of hierarchical electrode materials with nanocarbon networks, researchers can improve both the kinetic performance and the structural stability of the electrode material, which leads to optimal battery capacity, cycling stability, and rate capability. This Account summarizes recent progress in the structural design, chemical synthesis, and characterization of the electrochemical properties of nanocarbon networks for Li-ion batteries. In such systems, storage occurs primarily in the non-carbon components, while carbon acts as the conductor and as the structural buffer. We emphasize representative nanocarbon networks including those that use carbon nanotubes and graphene. We discuss the role of carbon in enhancing the performance of various electrode materials in areas such as Li storage, Li ion and electron transport, and structural stability during cycling. We especially highlight the use of graphene to construct the carbon conducting network for alloy anodes, such as Si and Ge, to accelerate electron transport, alleviate volume change, and prevent the agglomeration of active nanoparticles. Finally, we describe the power of nanocarbon networks for the next generation rechargeable lithium batteries, including Li-S, Li-O(2), and Li-organic batteries, and provide insights into the design of ideal nanocarbon networks for these devices. In addition, we address the ways in which nanocarbon networks can expand the applications of rechargeable lithium batteries into the emerging fields of stationary energy storage and transportation.

An optimized nanostructure design of Si-based anode material for high-performance lithium-ion batteries is realized in the form of Si/C nanoporous microspheres. Self-assembled Si/C nanoporous microspheres are synthesized by a programmed method and are investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, N2 adsorption–desorption isotherms, and electrochemical experiments. The programmed synthesis steps involve electrojetting Si nanoparticle-containing sodium alginate aqueous solution followed by calcination, carbon coating, and final etching. The electrospray step is the key step toward the formation of the microspheres in which sodium alginate acts as a dispersant and a carbon precursor for nano-Si particles as well as a coagulant together with Cu2+. The Si/C nanoporous microspheres exhibit remarkably enhanced cycling performance and rate performance compared with nano-Si particles when used as anode materials in lithium-ion batteries. The ...

Well-organized mesoporous TiO2−C nanospheres are manufactured in large scale starting from tetrabutyl titanate (TBT) and glucose in solution, and investigated with scanning electron microscopy, transmission electron microscopy, X-ray diffraction, N2 adsorption−desorption isotherms, and electrochemical experiments. The TiO2−C nanospheres show excellent rate capability and cycling performance for lithium ion batteries. At the extremely high rate of 100 C (discharge/charge within 36 s), the TiO2−C nanosphere can still deliver a specific capacity as high as 96 mA h g−1. Moreover, the as-obtained mesoporous TiO2−C nanosphere can be used as an anode material for a new high rate 1.5 V rechargeable Li ion full cell containing a LiFePO4−C cathode with similar mixed conducting 3D networks. This type of rechargeable battery typically gives an output of 1.5 V per cell, which raises the potential for directly replacing the widely used 1.5 V primary alkaline batteries and dry cells.