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Optimization of intrinsic structure of electrode materials plays decisive roles in promoting the development of energy storage systems to meet the fast-growing requirements in the market. Interlayer engineering has been proved to be an effective way to obtain adequate active sites, preferable ion diffusion channels and stable structure, thus enhance the performance of batteries. An in-depth understanding of the correlation among synthesis, structure and performance will significantly promote the development of excellent materials and energy storage devices. Therefore, in this review, recent advances in regards to cation preintercalation engineering in Mn-based electrode materials for rechargeable metal ion batteries are systematically summarized. Preintercalated guest cations can expand interlayer space to promote ion diffusion kinetics, serve as pillars to stabilize structure, control composition and valence to switch electrochemical behavior, thus improve the overall performance of secondary batteries. Moreover, the existing challenges and perspectives are provided for the interlayer engineering and its promotion to battery industry.

Sulfide-based solid electrolyte is one of the most promising solid electrolytes due to its high ionic conductivity and wide electrochemical window. However, it suffers from serious interfacial issues with lithium metal, which hinder the lithium-ion transport during cycling process and increase the interfacial resistance and instability. Protection only from Li anode side is not enough since Li enters into the bulk solid electrolyte resulting reaction and dendrite growth. Herein, we design a graphene oxide (GO) coated solid electrolyte Li7P3S11 particles for stable and efficient all-solid-state battery application. The GO could partially isolate the Li7P3S11 solid electrolyte from lithium metal. Meanwhile, the GO or rGO reduced by Li guide the homogeneous growth of Li and increase the cycling stability. Our work provides a facile method to fully protect Li7P3S11 in three directions from reaction with Li metal for dendrite-free and highly stable sulfide-based all-solid-state battery applications. This work might inspire the community with new material engineering/design strategies toward practical application in highly stable all solid state lithium-ion batteries.

Potassium-ion batteries (PIBs) have been regarded as promising alternatives to lithium-ion batteries in large-scale energy storage systems owing to the high abundance and low cost of potassium. However, the large radius of the K-ion hinders the development of suitable electrode materials. In this work, we confine SnS2 in N,S co-doped carbon nanofibers as anode materials for PIBs with high reversible capacity (457.4 mA h g−1@0.05 A g−1), remarkable cycling stability (1000 cycles@2.0 A g−1), and superior rate capability (219.4 mA h g−1@5.0 A g−1), overmatching most of the reported studies. The origin of the high reversible capacity is revealed by in situ XRD techniques. The combined capacitive and diffusion-controlled behaviors are disentangled through consecutive CV measurements. Combining the Randles–Sevcik equation and dQ/dV plots, correlations between the K-ion storage behaviors and diffusion kinetics at various potassiation depths are constructed. Theoretical calculations on K adsorption affinities at various N,S co-doped sites illuminate the synergistic effects of the N,S co-doping strategy in boosting the K-ion transport kinetics. Moreover, foldable potassium-ion full cells are successfully assembled with stable cycling performance, showing application potential in flexible electronic devices. These findings will boost the rational design and mechanistic understanding of anode materials in PIBs and related energy storage devices.

Lithium–oxygen (Li–O2) batteries are outstanding as next-generation energy-storage devices because of their extremely high theoretical specific energy density. However, their practical application ...

Rechargeable Li-O2 batteries (LOBs) have been receiving intensive attention because of their ultra-high theoretical energy density close to the gasoline. Herein, Ag modified urchin-like α-MnO2 (Ag-MnO2) material with hierarchical porous structure is obtained by a facile one-step hydrothermal method. Ag-MnO2 possesses thick nanowires and presents hierarchical porous structure of mesopores and macropores. The unique structure can expose more active sites, and provide continuous pathways for O2 and discharge products as well. The doping of Ag leads to the change of electronic distribution in a-MnO2 (i.e., more oxygen vacancies), which play important roles in improving their intrinsic catalytic activity and conductivity. As a result, LOBs with Ag-MnO2 catalysts exhibit lower overpotential, higher discharge specific capacity and much better cycle stability compared to pure α-MnO2. LOBs with Ag-MnO2 catalysts exhibit a superior discharge specific capacity of 13,131 mAhg−1 at a current density of 200 mAg−1, a good cycle stability of 500 cycles at the capacity of 500 mAhg−1. When current density is increased to 400 mAg−1, LOBs still retain a long lifespan of 170 cycles at a limited capacity of 1,000 mAhg−1.

High ionic conductivity and superior interfacial stability of solid electrolytes at the electrodes are crucial factors for high-performance all-solid-state sodium batteries. Herein, a composite solid electrolyte Na3PS4-polyethylene oxide is synthesized by the solution-phase reaction method with an improved ionic conductivity up to 9.4 × 10−5 S/cm at room temperature. Moreover, polyethylene oxide polymer layer is wrapped homogeneously on the surface of Na3PS4 particles, which could effectively avoid the direct contact between Na3PS4 electrolyte and sodium metal, thus alleviate their side reactions. We demonstrate that all-solid-state battery SnS2/Na with the composite solid electrolyte Na3PS4-polyethylene oxide delivers an enhanced electrochemical performance with 230 mAh/g after 40 cycles.

Rechargeable Li–air (O2) batteries have attracted a great deal of attention because of their high theoretical energy density and been regarded as a promising next-generation energy storage technolo...

Graphitic material has captured tremendous attentions as anode material for potassium ion batteries (PIBs). Nevertheless, the large radius of potassium-ions results in sluggish potassiation kinetics and huge volume expansion, leading to unsatisfying performance. Herein, a fabrication facile, cost-effective and high carbon yield nitrogen/oxygen co-doped amorphous carbon (NOC) with pitch and urea as precursors is reported. Pre-oxidation process is employed, maintaining the amorphous structure of pitch derived carbon against its soft carbon nature. The NOC electrode delivers reversible capacities of 347 (300th cycle) and 167 mAh g−1 (1000th cycle) at 100 and 2000 mA g−1, respectively. Rearrangement of graphene layers in short range benefits the structure stability against volume change. Kinetics analyses prove that surface-induced capacitive process dominates in K-ion storage mechanism, which contributes to the remarkable electrochemical performance. Pouch full cells were assembled, delivering a capacity of 316 mAh g−1 at 100 mA g−1. In view of the cost-effectiveness and electrochemical performance, this work offers a strategy for the fabrication of low-cost and high-performance PIB anode materials.

As high energy density and enhanced safety are required for the lithium-ion battery development, all-solid-state battery has attracted significant attention. Herein, we report an all-solid-state full battery consisting of a Li7P3S11 solid electrolyte coated silicon anode, Li2S/graphene composite cathode, and Li7P3S11 solid-state electrolyte. With a high capacity for the silicon anode and Li2S cathode, this battery yields a high theoretical specific energy density up to 1495 Wh kg−1, which is higher than that of lithium-ion batteries based on oxide cathodes. Moreover, Li2S cathode is used as lithium source instead of using metallic lithium, avoiding interface reaction between lithium metal anode and sulfide electrolyte Li7P3S11. This all-solid-state battery system we proposed could avoid the safety issues associated with the use of lithium metal and be a promising candidate for an enhanced energy density, which would promote their applications in the fields of electric vehicles and portable electronics.

To solve the critical issues like high polarization and unstable cycle ability, it is vital to design low-cost, stable and efficient catalytic cathode material for nonaqueous Li-O2 batteries (LOBs). Herein, a hollow urchin-like hollandite Ag2Mn8O16 electrocatalyst is fabricated by one-step hydrothermal method. The mixed bimetallic oxide with diverse valences (Mn3+ and Mn4+) and active oxygen defects provide sufficient active sites, and Ag Mn O bonds accelerate charge transformation. LOBs with the well-designed porous Ag2Mn8O16 cathode show superior electrochemical performances in LOBs, including ultrahigh specific capacity (7912 mAh gc−1 at 100 mA gc−1), good rate performance (5076 mAh gc−1 at 250 mA gc−1, 64.16%) and long-term cycle stability (320 cycles at 100 mA gc−1 within a limited capacity of 250 mAh gc−1 and 133 cycles at 200 mA gc−1 within a limited capacity of 500 mAh gc−1). This work provides a positive effect on designing better catalytic cathode materials for LOBs and push forward the commercialization progress.

With the advantages of high ionic conductivity and wide electrochemical window, sulfide-based solid electrolyte becomes a current research hotspot of all-solid-state lithium batteries. Nevertheless, severe interfacial problem between the sulfide electrolyte and lithium metal remains a great challenge, which can render a high interfacial resistance and hinder the transfer of lithium ions through interface, ultimately degrading the cycling performance. Furthermore, lithium dendrites easily form inside the electrolyte, thus accelerating the dendrite-induced shorting behavior of the battery. In this work, Li2S layer is in-situ coated on the surface of the sulfide solid electrolyte Li7P3S11 for highly stable lithium metal battery. The Li2S layer can effectively prevent Li7P3S11 from reacting with lithium metal. Meanwhile, the incorporation of the lithium sulfide can inhibit the generation and growth of internal lithium dendrites, thereby improving the cycling stability. The all-solid-state batteries based on the new designed electrolyte exhibit remarkably enhanced cycling stability. This work provides a simple and effective strategy to suppress lithium dendrite and promotes the practical application of sulfide-based all-solid-state batteries.

In this study, carbon-based iron nitride composite is prepared by hydrothermal synthesis, in-situ polymerization and nitriding, successively. The morphology, phase and chemical structure of the composite is characterized by scanning electron microscope (SEM), high resolution transmission electron microscopy (HRTEM), X-ray diffractometer (XRD) and Fourier transform infrared spectrometer (FTIR). The electromagnetic and microwave absorbing property of the composites is investigated using a vibrating sample magnetometer (VSM) and a vector network analyzer (VNA). The results show that the carbon-based iron nitride composite is successfully fabricated by coating Fe 4 N magnetic particles with thin carbon layers. The minimum reflection loss (RL) of −44 dB is observed at 4.23 GHz (3.02 mm thickness), and the frequency band is 3.72–4.74 GHz when RL ≤ −10 dB. When the thickness is reduced to 1.00 mm, the effective bandwidth (RL ≤ −10 dB) could still reach to 4.00 GHz. In summary, the carbon-based iron nitride composite shows excellent microwave absorbing property at 2–4 GHz with relatively thin thickness.

Lithium–oxygen batteries (LOBs) have attracted increasing interest because of their superior theoretical specific energy. However, the stability of lithium metal anode is one of the obstacles limiting their practical applications. Here, we introduce an artificial Li3PO4 solid electrolyte interphase (SEI) film to protect the lithium anode in LOB with LiI/LiNO3/DMSO (dimethyl sulfoxide) electrolyte. The Li3PO4-protected Li anode exhibits excellent electrochemical stability during the Li stripping/plating process and leads to a relatively uniform and featureless surface in LOB after cycling. Our research demonstrates that superior electrochemical performance can be achieved in the Li–O2 battery with the synergistic combination of the DMSO-based electrolyte, the LiI redox mediator, and the Li3PO4-protected Li anode. The LOB with a Li3PO4-protected Li anode exhibits a prolonged cycling life span of 152 cycles with a fixed capacity of 1000 mA h g–1 at 2 A g–1. The results in this work provide knowledge for the ...

Cations preintercalation is an effective way to optimize the crystal structure and improve the electrochemical behavior. An Ag+ pre-intercalated AgxMnO2 material with ultrafine nanowire structure is prepared by a facile hydrothermal method. With optimized crystalline microstructure including expanded interlayer space and introduced multivalence of Mn, the as-prepared material exhibits superior performance as cathode for both Li-ion and Na-ion hybrid supercapacitors (HSCs). High specific capacitance of 424.7 F g−1 in Li2SO4 electrolyte and 450.1 F g−1 in Na2SO4 system are achieved. The assembled HSCs using AgxMnO2 and activated carbon (YEC-8A) as electrode materials deliver a wide operation potential window of 0–2.2 V and a high energy density of 204.30 Wh kg−1 at the power density of 167.15 W kg−1 for Li-ion HSCs and 131.08 Wh kg−1 at 107.25 W kg−1 for Na-ion HSCs. Furthermore, the as-fabricated HSCs deliver excellent cyclic stability. The capacitance retention is 79.4% after 20,000 cycles for Li-ion HSC and 84.9% after 10,000 cycles for Na-ion HCS.

Conversion-alloying type anode materials like metal sulfides draw great attention due to their considerable theoretical capacity for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs). However, poor conductivity, severe volume change, and harmful aggregation of the material during charge/discharge lead to unsatisfying electrochemical performance. Herein, a facile and green strategy for yolk-shell structure based on the principle of metal evaporation is proposed. SnS2 nanoparticle is encapsulated in nitrogen-doped hollow carbon nanobox (SnS2 @C). The carbon nanoboxes accommodate the volume change and aggregation of SnS2 during cycling, and form 3D continuous conductive carbon matrix by close contact. The well-designed structure benefits greatly in conductivity and structural stability of the material. As expected, SnS2 @C exhibits considerable capacity, superior cycling stability, and excellent rate capability in both SIBs and PIBs. Additionally, in situ Raman technology is unprecedentedly conducted to investigate the phase evolution of polysulfides. This work provides an avenue for facilely constructing stable and high-capacity metal dichalcogenide based anodes materials with optimized structure engineering. The proposed in-depth electrochemical measurements coupled with in situ and ex situ characterizations will provide fundamental understandings for the storage mechanism of metal dichalcogenides.

Silicon with higher theoretical capacity than that of the commercial graphite anode is considered as the next generation lithium ion battery anode materials. Herein, our research demonstrates that the surface SiOx coating with silanol groups generated in aqueous solution on silicon nanoparticles can efficiently improve their electrochemical performance. The SiOx layer can suppress the volume expansion of silicon particles, and the surficial silanol groups can also contribute to the enhanced electrochemical performance. Both coulombic efficiency and cycling stability can be improved with the optimal SiOx coating thickness. This work provides a facile avenue of surface engineering of silicon nanoparticle for the high-performance lithium ion battery Si anode.

Polyethylene-oxide (PEO)-based electrolyte is one of the most promising solid electrolytes due to its outstanding safety and excellent flexibility. However, the most common method to fabricate PEO-based electrolyte is casting, which requires intensive use of toxic organic solvent. Besides, the agglomeration of filler in the composite electrolyte fabricated by casting limits further enhancement of ionic conductivity. In this work, we provide a facile solvent-free cold-pressing method to prepare well-dispersed LAGP @ PEO composite solid-state electrolyte. The ionic conductivity of LAGP @ PEO composite electrolyte can reach about 4.4 × 10−5 S cm−1 at room temperature which is nearly one order of magnitude higher than that of the casting one (3.3 × 10−6 S cm−1). The integrated all-solid-state batteries display excellent cycling stability and good rate performance at 50 °C. Our work provides a facile solvent-free cold-pressing method to fabricate polymer-based composite electrolyte with well-dispersed filler for all-solid-state batteries.

Li-O 2 batteries are considered as one of the future candidates for electrochemical power sources due to their high theoretical energy density. As the dominating component affects the performance of Li-O 2 batteries, O 2 -cathode catalyst with high efficiency, low price, facile preparation is important. Herein, polyhedral and porous Mn 2 O 3 rods are fabricated for cathode catalysts in Li-O 2 batteries via electrospinning method followed by calcination. The Mn 2 O 3 catalyst possesses a three-dimensional porous structure, which can offer good catalytic activity, expose plenty of active sites and improve the diffusion of electrolyte and O 2 . When employed as the cathode catalyst, the Li-O 2 batteries show enhanced initial discharge capacity of 9701 mA h g −1 at a current density of 200 mA g −1 , superior rate capacity and good cycling stability within 160 cycles at the capacity of 500 mA h g −1 . These enhanced performances demonstrate a facile method to fabricate Mn 2 O 3 with unique structure as a promising catalytic material for Li-O 2 batteries.