Intercalated Electrolyte with High Transference Number for Dendrite‐Free Solid‐State Lithium Batteries

Solid‐state lithium (Li) batteries using solid electrolytes and Li anodes are highly desirable because of their high energy densities and intrinsic safety. However, low ambient‐temperature conductivity and poor interface compatibility of solid electrolytes as well as Li dendrite formation cause large polarization and poor cycling stability. Herein, a high transference number intercalated composite solid electrolyte (CSE) is prepared by the combination of a solution‐casting and hot‐pressing method using layered lithium montmorillonite, poly(ethylene carbonate), lithium bis(fluorosulfonyl)imide, high‐voltage fluoroethylene carbonate additive, and poly(tetrafluoroethylene) binder. The electrolyte presents high ionic conductivity (3.5 × 10^?4 S cm^?1), a wide electrochemical window (4.6 V vs Li⁺/Li), and high ionic transference number (0.83) at 25 °C. In addition, a 3D Li anode is also fabricated via a facile thermal infusion strategy. The synergistic effect of high transference number intercalated electrolyte and 3D Li anode is more favorable to suppress Li dendrites in a working battery. The solid‐state batteries based on LiFePO₄ (Al₂O₃ @ LiNi_0.5Co_0.2Mn_0.3O₂), CSE, and 3D Li deliver admirable cycling stability with discharge capacity 145.9 mAh g^?1 (150.7 mAh g^?1) and capacity retention 91.9% after 200 cycles at 0.5 C (92.0% after 100 cycles at 0.2 C) at 25 °C. This work affords a splendid strategy for high‐performance solid‐state battery.     

Rechargeable Na–SO2 Battery with Ethylenediamine Additive in Ether‐Based Electrolyte

Rechargeable metal–SO₂ batteries have drawn tremendous attention because it can accelerate SO₂ fixation/utilization and offer high energy density. Herein, a rechargeable Na–SO₂ battery based on an ether‐based liquid electrolyte with an ethylenediamine (EDA) additive is realized via the reversible formation/decomposition of Na₂S₂O₄. Experimental investigations reveal that the EDA additive provides three benefits by simultaneously decreasing the overall electrode polarization, increasing the full discharge capacity, and improving battery cyclability. At a current density of 250 mA g^?1, the full discharge capacity of the battery with the EDA additive is more than twice of a similar system in the absence of EDA. In addition to the significantly enhanced capacity, the as‐assembled Na–SO₂ battery demonstrates excellent cyclic stability after 200 cycles, which is equivalent to a total duration of 1600 h. Moreover, the corrosion resistance of Na anode is strengthened with the aid of EDA in the SO₂‐containing liquid electrolyte. This work will pave the way for Na–SO₂ batteries as a promising battery technology toward both pollutant gas utilization and energy storage.     

A New Triclinic Phase Na2Ti3O7 Anode for Sodium‐Ion Battery

A new phase Na₂Ti₃O₇ compound is synthesized by solid‐state method for the first time, which is verified to belong to the triclinic structure in P‐1 space group. Compared to the conventional monoclinic Na₂Ti₃O₇ (m‐NTO), in P2₁/m1 space group, the triclinic Na₂Ti₃O₇ (t‐NTO) possesses a shorter O‐O band in the distorted TiO₆ octahedron, which accounts for more smooth Na⁺ transport channels and a more stable layered structure with smaller fluctuation. The experimental results show that the t‐NTO keeps a low charge potential plateau at 0.3 V compared to the m‐NTO, but with much promoted structure resilience. It delivers a capacity retention of 94.7%, far exceeding the 25.7% of the m‐NTO upon decades of cycles. In situ X‐ray diffraction reveals that the conventional m‐NTO experiences an irreversible phase transition during insertion/de‐insertion of Na⁺, while the new t‐NTO can recover its structure reversibly after discharge and charge, which is consistent with its improved cycling performance. The results demonstrate a new t‐NTO anode and provide a new understanding for the phase diversity of sodium‐ion battery materials.     

Associating and Tuning Sodium and Oxygen Mixed‐Ion Conduction in Niobium‐Based Perovskites

Pure ionic conductors as solid‐state electrolytes are of high interest in electrochemical energy storage and conversion devices. They systematically involve only one ion as the charge carrier. The association of two mobile ionic species, one positively and the other negatively charged, in a specific network should strongly influence the total ion conduction. Nb⁵⁺‐ (4d⁰) and Ti⁴⁺‐based (3d⁰) derived‐perovskite frameworks containing Na⁺ and O^2? as mobile species are investigated as mixed ion conductors by electrochemical impedance spectroscopy. The design of Na⁺ blocking layers via sandwiched pellet sintered by spark plasma sintering at high temperatures leads to quantified transport number of both ionic charge carriers t_Na+ and t_O2?. In the 350–700 °C temperature range, ionic conductivity can be tuned from major Na⁺ contribution (t_Na+ = 88%) for NaNbO₃ to pure O^2? transport in NaNb_0.9Ti_0.1O_2.95 phase. Such a Ti‐substitution is accompanied with a ≈100‐fold increase in the oxygen conductivity, approaching the best values for pure oxygen conductors in this temperature range. Besides the demonstration of tunable mixed ion conduction with quantifiable cationic and anionic contributions in a single solid‐state structure, a strategy is established from structural analysis to develop other architectures with improved mixed ionic conductivity.     

High‐Performance,Low‐Cost,and Dense‐Structure Electrodes with High Mass Loading for Lithium‐Ion Batteries

Lithium‐ion batteries have undergone a remarkable development in the past 30 years. However, conventional electrodes are insufficient for the ever‐increasing demand of high‐energy batteries. Here, reported is a thick electrode with a dense structure, as an alternative to the commonly recognized porous framework. A low‐temperature sintering technology with the aid of aqueous solvent, high pressure, and an ion‐conductive additive is originally developed for preparing the LiCoO₂ (LCO)/Li₄Ti₅O₁₂ (LTO) dense‐structure electrode as the representative cathode/anode material. The 400 µm thick cathode with 110 mg cm^?2 mass loading achieves a high specific capacity of 131.2 mAh g^?1 with a good capacity retention of 96% over 150 cycles, far exceeding the commercial counterpart (≈40 µm) of 54.1 mAh g^?1 with 39%. The ultrathick electrode of 1300 µm thickness presents a remarkable area capacity of 28.6 mAh cm^?2 that is 16 times that of the commercial electrode. The full cell based on the dense electrodes delivers an extremely high areal capacity of 14.4 mAh cm^?2. The ion‐diffusion coefficients of the densely sintered electrodes increase by nearly three orders of magnitude. This design opens up a new avenue for scalable and sustainable material manufacturing towards various practical applications.     

Carbon‐Stabilized High‐Capacity Ferroferric Oxide Nanorod Array for Flexible Solid‐State Alkaline Battery–Supercapacitor Hybrid Device with High Environmental Suitability

Iron oxides are promising to be utilized in rechargeable alkaline battery with high capacity upon complete redox reaction (Fe³⁺ Fe⁰). However, their practical application has been hampered by the poor structural stability during cycling, presenting a challenge that is particularly huge when binder‐free electrode is employed. This paper proposes a “carbon shell‐protection” solution and reports on a ferroferric oxide–carbon (Fe₃O₄–C) binder‐free nanorod array anode exhibiting much improved cyclic stability (from only hundreds of times to >5000 times), excellent rate performance, and a high capacity of ≈7776.36 C cm^?3 (≈0.4278 C cm^?2; 247.5 mAh g^?1, 71.4% of the theoretical value) in alkaline electrolyte. Furthermore, by pairing with a capacitive carbon nanotubes (CNTs) film cathode, a unique flexible solid‐state rechargeable alkaline battery‐supercapacitor hybrid device (≈360 μm thickness) is assembled. It delivers high energy and power densities (1.56 mWh cm^?3; 0.48 W cm^?3/≈4.8 s charging), surpassing many recently reported flexible supercapacitors. The highest energy density value even approaches that of Li thin‐film batteries and is about several times that of the commercial 5.5 V/100 mF supercapacitor. In particular, the hybrid device still maintains good electrochemical attributes in cases of substantially bending, high mechanical pressure, and elevated temperature (up to 80 °C), demonstrating high environmental suitability.     

Electrochemical Na Insertion and Solid Electrolyte Interphase for Hard‐Carbon Electrodes and Application to Na‐Ion Batteries

Recently, lithium‐ion batteries have been attracting more interest for use in automotive applications. Lithium resources are confirmed to be unevenly distributed in South America, and the cost of the lithium raw materials has roughly doubled from the first practical application in 1991 to the present and is increasing due to global demand for lithium‐ion accumulators. Since the electrochemical equivalent and standard potential of sodium are the most advantageous after lithium, sodium based energy storage is of great interest to realize lithium‐free high energy and high voltage batteries. However, to the best of our knowledge, there have been no successful reports on electrochemical sodium insertion materials for battery applications; the major challenge is the negative electrode and its passivation. In this study, we achieve high capacity and excellent reversibility sodium‐insertion performance of hard‐carbon and layered NaNi_0.5Mn_0.5O₂ electrodes in propylene carbonate electrolyte solutions. The structural change and passivation for hard‐carbon are investigated to study the reversible sodium insertion. The 3‐volt secondary Na‐ion battery possessing environmental and cost friendliness, Na⁺‐shuttlecock hard‐carbon/NaNi_0.5Mn_0.5O₂ cell, demonstrates steady cycling performance as next generation secondary batteries and an alternative to Li‐ion batteries.     

Sodium‐Ion Batteries: Building Effective Layered Cathode Materials with Long‐Term Cycling by Modifying the Surface via Sodium Phosphate

Surface stabilization of cathode materials is urgent for guaranteeing long‐term cyclability, and is important in Na cells where a corrosive Na‐based electrolyte is used. The surface of P2‐type layered Na_2/3[Ni_1/3Mn_2/3]O₂ is modified with ionic, conducting sodium phosphate (NaPO₃) nanolayers, ≈10 nm in thickness, via melt‐impregnation at 300 °C; the nanolayers are autogenously formed from the reaction of NH₄H₂PO₄ with surface sodium residues. Although the material suffers from a large anisotropic change in the c‐axis due to transformation from the P2 to O2 phase above 4 V versus Na⁺/Na, the NaPO₃‐coated Na_2/3[Ni_1/3Mn_2/3]O₂/hard carbon full cell exhibits excellent capacity retention for 300 cycles, with 73% retention. The surface NaPO₃ nanolayers positively impact the cell performance by scavenging HF and H₂O in the electrolyte, leading to less formation of byproducts on the surface of the cathodes, which lowers the cell resistance, as evidenced by X‐ray photoelectron spectroscopy and time‐of‐flight secondary‐ion mass spectroscopy. Time‐resolved in situ high‐temperature X‐ray diffraction study reveals that the NaPO₃ coating layer is delayed for decomposition to Mn₃O₄, thereby suppressing oxygen release in the highly desodiated state, enabling delay of exothermic decomposition. The findings presented herein are applicable to the development of high‐voltage cathode materials for sodium batteries.     

Stabilizing High-Nickel Cathodes with High-Voltage Electrolytes

Electrolytes connect the two electrodes in a lithium battery by providing Li⁺ transport channels between them. Advanced electrolytes are being explored with high-nickel cathodes and the lithium-metal anode to meet the high energy density and cycle life goals, but the origin of the performance differences with different electrolytes is not fully understood. Here, the mechanisms involved in protecting the high-capacity, cobalt-free cathode LiNiO₂ with a model high-voltage electrolyte (HVE) are delineated. The kinetic barrier posed by a thick surface degradation layer with poor Li⁺-ion transport is found to be the major contributor to the fast capacity fade of LiNiO₂ with the conventional carbonate electrolyte. In contrast, HVE reduces the side reactions between the electrolyte and the electrodes, leading to a thinner nano-interphase layer comprised of more beneficial species. Crucially, the HVE leads to a different surface reorganization pathway involving the formation of a thinner nanoscale LiNi₂O₄ spinel phase on the LiNiO₂ surface. With a high 3D Li⁺-ion and electronic conductivity, the spinel LiNi₂O₄ reorganization nanolayer preserves fast Li⁺ transport across the cathode–electrolyte interface, reduces reaction heterogeneity in the electrode and alleviates intergranular cracking within secondary particles, resulting in superior long-term cycle life.     

A Flexible Dual‐Ion Battery Based on Sodium‐Ion Quasi‐Solid‐State Electrolyte with Long Cycling Life

Sodium‐based dual‐ion batteries (SDIBs) have attracted much attention for their advantages of high operating voltage, environmental friendliness, and especially low cost. However, the electrochemical performances of the reported SDIBs are still unsatisfied due to the decomposition problem of traditional liquid electrolyte under high working voltage. Development of quasi‐solid‐state electrolytes (QSSEs) with excellent electrochemical stability at high voltage is a possible means to improve their properties. In this work, a flexible SDIB based on a QSSE, consisting of poly(vinylidene ?uoride‐co‐hexa?uoropropylene) (PVDF‐HFP) three‐dimensionally cross‐linked with Al₂O₃ nanoparticles, which exhibits a porous 3D structure with dramatically enhanced ionic conductivity up to ≈1.3 × 10^?3 S cm^?1, facilitating fast ionic migration of both anions and cations, is reported. This quasi‐state SDIB exhibits a high specific capacity of 96.8 mAh g^?1 at a current rate of 5 C and excellent cycling stability with a capacity retention of 97.5% after 600 cycles at 5 C, which is the best performance of the SDIBs. Moreover, excellent flexibility and a wide working temperature range (?20 to 70 °C) have been realized for this battery, suggesting its potential for high‐performance flexible energy storage applications.     

MXene‐Bonded Flexible Hard Carbon Film as Anode for Stable Na/K‐Ion Storage

Hard carbon (HC) is a promising anode material for sodium‐ion batteries (SIBs) and potassium‐ion batteries (PIBs), but the volume change during the insertion/extraction of Na⁺ or K⁺ limits the cycle life, especially for PIBs due to the large ion size of K⁺. Moreover, the conventional anodes fabricated through the coating method cannot satisfy the requirement of flexible devices. Here, it is shown that 2D carbide flakes of Ti₃C₂T_x MXene can be used as multifunctional conductive binders for flexible HC electrodes. The use of MXene nanosheets eliminates the need for all the electrochemically inactive components in the conventional polyvinylidene fluoride–bonded HC electrode, including polymer binders, conductive additives, and current collectors. In MXene‐bonded HC electrodes, conductive and hydrophilic MXene 2D nanosheets construct a 3D network, which can effectively stabilize the electrode structure and accommodate the volume expansion of HC during the charge/discharge process, leading to an enhanced electrode capacity and excellent cycle performance as anodes for both SIBs and PIBs. Benefiting from the 3D conductive network, the MXene‐bonded HC film electrodes also present improved rate capability, indicating MXene is a very promising multifunctional binder for next‐generation flexible secondary rechargeable batteries.     

Enhanced Cycling Stability of Rechargeable Li–O2 Batteries Using High‐Concentration Electrolytes

The stability of electrolytes against highly reactive, reduced oxygen species is crucial for the development of rechargeable Li–O₂ batteries. In this work, the effect of lithium salt concentration in 1,2‐dimethoxyethane (DME)‐based electrolytes on the cycling stability of Li–O₂ batteries is investigated systematically. Cells with highly concentrated electrolyte demonstrate greatly enhanced cycling stability under both full discharge/charge (2.0–4.5 V vs Li/Li⁺) and the capacity‐limited (at 1000 mAh g^?1) conditions. These cells also exhibit much less reaction residue on the charged air‐electrode surface and much less corrosion of the Li‐metal anode. Density functional theory calculations are used to calculate molecular orbital energies of the electrolyte components and Gibbs activation energy barriers for the superoxide radical anion in the DME solvent and Li⁺–(DME) _n solvates. In a highly concentrated electrolyte, all DME molecules are coordinated with salt cations, and the C–H bond scission of the DME molecule becomes more difficult. Therefore, the decomposition of the highly concentrated electrolyte can be mitigated, and both air cathodes and Li‐metal anodes exhibit much better reversibility, resulting in improved cyclability of Li–O₂ batteries.     

Three Electron Reversible Redox Reaction in Sodium Vanadium Chromium Phosphate as a High‐Energy‐Density Cathode for Sodium‐Ion Batteries

A sodium‐ion battery operating at room temperature is of great interest for large‐scale stationary energy storage because of its intrinsic cost advantage. However, the development of a high capacity cathode with high energy density remains a great challenge. In this work, sodium super ionic conductor‐structured Na₃V_2?xCr_x(PO₄)₃ is achieved through the sol–gel method; Na₃V_1.5Cr_0.5(PO₄)₃ is demonstrated to have a capacity of 150 mAh g^?1 with reversible three‐electron redox reactions after insertion of a Na⁺, consistent with the redox couples of V²⁺/³⁺, V³⁺/⁴⁺, and V⁴⁺/⁵⁺. Moreover, a symmetric sodium‐ion full cell utilizing Na₃V_1.5Cr_0.5(PO₄)₃ as both the cathode and anode exhibits an excellent rate capability and cyclability with a capacity of 70 mAh g^?1 at 1 A g^?1. Ex situ X‐ray diffraction analysis and in situ impedance measurements are performed to reveal the sodium storage mechanism and the structural evolution during cycling.     

Enhancing the Performance of Solid‐State Dye‐Sensitized Solar Cells Using a Mesoporous Interfacial Titania Layer with a Bragg Stack

High efficiency dye‐sensitized solar cells (DSSCs) are fabricated with a heterostructured photoanode that consists of a 500‐nm‐thick organized mesoporous TiO₂ (om‐TiO₂) interfacial layer (IF layer), a 7 or 10‐μm thick nanocrystalline TiO₂ layer (NC layer), and a 2‐μm‐thick mesoporous Bragg stack (meso‐BS layer) as the bottom, middle and top layers, respectively. An om‐TiO₂ layer with a high porosity, transmittance, and interconnectivity is prepared via a sol‐gel process, in which a poly(vinyl chloride)‐g‐poly(oxyethylene methacrylate) (PVC‐g‐POEM) graft copolymer is used as a structure‐directing agent. The meso‐BS layer with large pores is prepared via alternating deposition of om‐TiO₂ and colloidal SiO₂ (col‐SiO₂) layers. Structure and optical properties (refractive index) of the om‐TiO₂ and meso‐BS layers are studied and the morphology of the heterostructured photoanode is characterized. DSSCs fabricated with the heterostructured IF/NC/BS photoanode and combined with a polymerized ionic liquid (PIL) exhibit an energy conversion efficiencies of 6.6% at 100 mW/cm², one of the highest reported for solid‐state DSSCs and much larger than cells prepared with only a IF/NC layer (6.0%) or a NC layer (4.5%). Improvements in energy conversion efficiency are attributed to the combination of improved light harvesting, decreased resistance at the electrode/electrolyte interface, and excellent electrolyte infiltration.     

Interlayer Engineering of Molybdenum Trioxide toward High‐Capacity and Stable Sodium Ion Half/Full Batteries

Orthorhombic molybdenum trioxide (MoO₃) is one of the most promising anode materials for sodium‐ion batteries because of its rich chemistry associated with multiple valence states and intriguing layered structure. However, MoO₃ still suffers from the low rate capability and poor cycle induced by pulverization during de/sodiation. An ingenious two‐step synthesis strategy to fine tune the layer structure of MoO₃ targeting stable and fast sodium ionic diffusion channels is reported here. By integrating partially reduction and organic molecule intercalation methodologies, the interlayer spacing of MoO₃ is remarkably enlarged to 10.40 Å and the layer structural integration are reinforced by dimercapto groups of bismuththiol molecules. Comprehensive characterizations and density functional theory calculations prove that the intercalated bismuththiol (DMcT) molecules substantially enhanced electronic conductivity and effectively shield the electrostatic interaction between Na⁺ and the MoO₃ host by conjugated double bond, resulting in improved Na⁺ insertion/extraction kinetics. Benefiting from these features, the newly devised layered MoO₃ electrode achieves excellent long‐term cycling stability and outstanding rate performance. These achievements are of vital significance for the preparation of sodium‐ion battery anode materials with high‐rate capability and long cycling life using intercalation chemistry.     

Understanding Origin of Voltage Hysteresis in Conversion Reaction for Na Rechargeable Batteries: The Case of Cobalt Oxides

Conversion reaction electrodes offer a high specific capacity in rechargeable batteries by utilizing wider valence states of transition metals than conventional intercalation‐based electrodes and have thus been intensively studied in recent years as potential electrode materials for high‐energy‐density rechargeable batteries. However, several issues related to conversion reactions remain poorly understood, including the polarization or hysteresis during charge/discharge processes. Herein, Co₃O₄ in Na cells is taken as an example to understand the aforementioned properties. The large hysteresis in charge/discharge profiles is revealed to be due to different electrochemical reaction paths associated with respective charge and discharge processes, which is attributed to the mobility gap among inter‐diffusing species in a metal oxide compound during de/sodiation. Furthermore, a Co₃O₄–graphene nanoplatelet hybrid material is demonstrated to be a promising anode for Na rechargeable batteries, delivering a capacity of 756 mAh g^?1 with a good reversibility and an energy density of 96 Wh kg^?1 (based on the total electrode weight) when combined with a recently reported Na₄Fe₃(PO₄)₂(P₂O₇) cathode.     

Hierarchical Engineering of Porous P2‐Na2/3Ni1/3Mn2/3O2 Nanofibers Assembled by Nanoparticles Enables Superior Sodium‐Ion Storage Cathodes

Layered transition metal oxides (TMOs) are appealing cathode candidates for sodium‐ion batteries (SIBs) by virtue of their facile 2D Na⁺ diffusion paths and high theoretical capacities but suffer from poor cycling stability. Herein, taking P2‐type Na_2/3Ni_1/3Mn_2/3O₂ as an example, it is demonstrated that the hierarchical engineering of porous nanofibers assembled by nanoparticles can effectively boost the reaction kinetics and stabilize the structure. The P2‐Na_2/3Ni_1/3Mn_2/3O₂ nanofibers exhibit exceptional rate capability (166.7 mA h g^?1 at 0.1 C with 73.4 mA h g^?1 at 20 C) and significantly improved cycle life (≈81% capacity retention after 500 cycles) as cathode materials for SIBs. The highly reversible structure evolution and Ni/Mn valence change during sodium insertion/extraction are verified by in operando X‐ray diffraction and ex situ X‐ray photoelectron spectroscopy, respectively. The facilitated electrode process kinetics are demonstrated by an additional study using the electrochemical measurements and density functional theory computations. More impressively, the prototype Na‐ion full battery built with a Na_2/3Ni_1/3Mn_2/3O₂ nanofibers cathode and hard carbon anode delivers a promising energy density of 212.5 Wh kg^?1. The concept of designing a fibrous framework composed of small nanograins offers a new and generally applicable strategy for enhancing the Na‐storage performance of layered TMO cathode materials.     

Constructing CoO/Co3S4 Heterostructures Embedded in N‐doped Carbon Frameworks for High‐Performance Sodium‐Ion Batteries

Heterostructures are attractive for advanced energy storage devices due to their rapid charge transfer kinetics, which is of benefit to the rate performance. The rational and facile construction of heterostructures with satisfactory electrochemical performance, however, is still a great challenge. Herein, ultrafine hetero‐CoO/Co₃S₄ nanoparticles embedded in N‐doped carbon frameworks (CoO/Co₃S₄@N‐C) are successfully obtained by employing metal‐organic frameworks as precursors. As anodes for sodium ion batteries, the CoO/Co₃S₄@N‐C electrodes exhibit high specific capacity (1029.5 mA h g^?1 at 100 mA g^?1) and excellent rate capability (428.0 mA h g^?1 at 5 A g^?1), which may be attributed to their enhanced electric conductivity, facilitated Na⁺ transport, and intrinsic structural stability. Density functional theoretical calculations further confirm that the constructed heterostructures induce electric fields and promote fast reaction kinetics in Na⁺ transport. This work provides a feasible approach to construct metal oxide/sulfide heterostructures toward high‐performance metal‐ion batteries.     

A Sieve‐Functional and Uniform‐Porous Kaolin Layer toward Stable Zinc Metal Anode

Zinc metal is considered as one of the best anode choices for rechargeable aqueous Zn‐based batteries due to its high specific capacity, abundance, and safety. However, dendrite and corrosion issues remain a challenge for this system. Herein, sieve‐element function (selective channel of Zn²⁺) and uniform‐pore distribution (≈3.0 nm) of a kaolin‐coated Zn anode (KL‐Zn) is proposed to alleviate these problems. Based on the artificial Zn metal/electrolyte interface, the KL‐Zn anode not only ensures dendrite‐free deposition and long‐time stability (800 h at 1.1 mA h cm^?2), but also retards side reactions. As a consequence, KL‐Zn/MnO₂ batteries can deliver high specific capacity and good capacity retention as well as a reasonably well‐preserved morphology (KL‐Zn) after 600 cycles at 0.5 A g^?1. This work provides a deep step toward high‐performance rechargeable Zn‐based battery system.     

Solid‐State Electrode Materials with Ionic‐Liquid Properties for Energy Storage: the Lithium Solid‐State Ionic‐Liquid Concept.

Herein, the novel concept of a solid‐state electrode materials with ionic‐liquid (IL) properties is presented. These composite materials are a mixture of electroactive matter, an electronic conductor, a solid‐state ionic conductor and a polymeric binder. The approach of a solid‐state ionic conductor combines the high safety of an IL with the nanoconfinement of such a liquid in a mesoporous silica framework, an ionogel, thus leading to a solid with liquid‐like ionic properties. The same ionic conductor is also used as a solid‐state separator to evaluate the properties of our solid‐state electrode materials in all‐solid‐state batteries. Such a concept of a solid‐state electrode material contributes to addressing the challenge of energy storage, which is one of the major challenges of the 21^st century. The ionogel, along with its processability, allows a single‐step preparation of the assembly of the solid‐state electrode and solid‐electrolyte separator and can be applied without specific adaptation to present, thick electrodes prepared by the widespread tape‐casting technique. The filling of the electrode porosity by an ionogel is shown by elemental mapping using scanning electron microscopy, and is subsequently confirmed by electrochemical measurements. The ionogel approach is successfully applied without specific adaptation to two state‐of‐the‐art, positive electroactive materials developed for future‐generation lithium‐ion batteries, namely LiFePO₄ and LiNi_1/3Mn_1/3Co_1/3O₂.