increased and the energy transform efficiency decreased. For the SPEs in which the Li + are transport by moieties on the polymer chain, their ionic conductivity and electrochemical stability is restricted by the polymer structure, typically, polyethylene oxide (PEO) based SPEs only working in high temperature above 60 °C and at low voltage of below 4.0 V.Ceramic/polymer hybrid solid electrolyte (HSE) is a promising material by combining the advantages of both types of electrolytes, typical HSEs are composed of polymers to enhance the electrode/ electrolyte interfacial compatibility and inorganic fillers to adjust the ionic transportability. [8][9][10][11][12][13][14][15][16][17][18] The fillers could be metal oxides, such as Al 2 O 3 , [10] SiO 2 , [11,12] TiO 2 , [13] and Fe 2 O 3 [14] or fast Li + conductors, such as Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP), [15] LLZO, [16,17] and LGPS, [18] the materials can not only reduce the polymer matrix crystallinity, but also provide extra diffusion routes for Li + , thus enhance the overall performance of the electrolyte. Mechanical mixing is the most common method to obtain the HSE, and it is convenient and cost-effective. However, the composite electrolyte obtained by this method often shows poor uniformity and the fillers are fail to form interconnected Li + conduct channels, on which ionic conductivity of the composites cannot be enhanced effectively. [11] The other issue bring about by mechanical mixing is the organic/inorganic electrolyte interfacial compatibility, as ions inclined to flow along the low resistance pathways, [6,19] local difference in conductivity may lead to strong space charge layer at the interphase and cause polymer oxidation. Many methods were attempted to optimize this interphase compatibility such as reducing particle size of ceramic, [20,21] making the ceramic fillers orderly, and higher dimension. [22,23] But such problem still exists and the interfacial compatibility cannot be neglected. Making chemical bond is a new strategy to resolve the issue of interface. [24][25][26] Nan's group utilized the catalysis of La in dehydrofluorination and prepared poly(vinylidenefluoride) (PVDF)-Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 (LLZTO) HSE whose ionic conductivity is as high as 5 × 10 −4 S cm −1 at 25 °C. [26] But this strategy can only be applied to those polymers consisting of H and F in neighbor carbon atoms such as PVDF or poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) [24] which cannot contribute to ionic transport. Archer's group proposed a more universal method by preparing a kind of soft colloidal glasses HSE that PEO chains were covalently grafted onto silica nanoparticles. The HSE works stable in high-voltage nickel cobalt manganese Ceramic/polymer hybrid solid electrolytes (HSEs) have attracted worldwide attentions because they can overcome defects by combining the advantages of ceramic electrolytes (CEs) and solid polymer electrolytes (SPEs). However, the interface compatibility of CEs and SPEs in HSE limits their full function to...

No abstract

Light‐driven generation of H2O2 only from water and molecular oxygen could be an ideal pathway for clean production of solar fuels. In this work, a mixed metal oxide/graphitic‐C3N4 (MMO@C3N4) composite was synthesized as a dual‐functional photocatalyst for both water oxidation and oxygen reduction to generate H2O2. The MMO was derived from a NiFe‐layered double hydroxide (LDH) precursor for obtaining a high dispersion of metal oxides on the surface of the C3N4 matrix. The C3N4 is in the graphitic phase and the main crystalline phase in MMO is cubic NiO. The XPS analyses revealed the doping of Fe3+ in the dominant NiO phase and the existence of surface defects in the C3N4 matrix. The formation and decomposition kinetics of H2O2 on the MMO@C3N4 and the control samples, including bare MMO, C3N4 matrix, Ni‐ or Fe‐loaded C3N4 and a simple mixture of MMO and C3N4, were investigated. The MMO@C3N4 composite produced 63 μmol L−1 of H2O2 in 90 min in acidic solution (pH 3) and exhibited a significantly higher rate of production for H2O2 relative to the control samples. The positive shift of the valence band in the composite and the enhanced water oxidation catalysis by incorporating the MMO improved the light‐induced hole collection relative to the bare C3N4 and resulted in the enhanced H2O2 formation. The positively shifted conduction band in the composite also improved the selectivity of the two‐electron reduction of molecular oxygen to H2O2.

Conspectus All-solid-state lithium batteries have received considerable attention in recent years with the ever-growing demand for efficient and safe energy storage technologies. However, key issues remain unsolved and hinder full-scale commercialization of all-solid-state lithium batteries. Previously, most discussion only focused on how to achieve high energy density from the theoretical perspective. Herein, we analyze the real cases of different kinds of all-solid-state lithium batteries with high energy density to understand the current status, including all-solid-state lithium-ion batteries, all-solid-state lithium metal batteries, and all-solid-state lithium–sulfur batteries. First, we propose a general calculation method to visually compare the above battery systems partly due to no normative parameters for solid-state batteries. After then, we discuss and interpret the key parameters and current situation of all-solid-state lithium batteries. Through the summary and analysis of the frontier, one can find that, although some breakthrough has been made in energy density and areal capacity for solid-state batteries, there are still many aspects to be improved such as power density and rate performance. Therefore, in response to the challenges, we propose possible directions for future development, including the ways to prepare different kinds of solid electrolyte films to reduce the proportion of inactive substances in the cell. The advantages and disadvantages are discussed about three typical solid-state electrolyte films (inorganic solid electrolyte, solid polymer electrolyte, and composite solid electrolyte). In addition, potential candidate anodes with high capacity and cathodes with high voltage and/or high capacity are also discussed in details. The combination of lithium metal anodes with ultrahigh capacity and cathodes with both high capacity and high voltage is the current mainstream direction. However, the interface problems have become the most pressing factor on the application. Therefore, we introduce the origin of interfaces and interphases and discuss how to build a stable electrode/solid electrolyte interface. One thing is clear that artificial solid electrolyte interphases and composite solid electrolytes are effective to obtain stable anode/solid electrolyte interfaces, which can prevent lithium from constantly reacting with solid electrolytes, ensure the uniform lithium deposition and prevent the formation of lithium dendrites. For the cathode/solid electrolyte interface, reasonable composite cathodes, multilayer design, and composite solid electrolytes can optimize the electrode and interface for stable cycles at high voltages and high current densities. Furthermore, the contribution of high-throughput computations and machine learning is introduced in accelerating materials screening and development. Among them, progress has been made in solid electrolytes and artificial solid electrolyte interphases through materials genome engineering and machine learning. Finally, we provide some out...