Hou Yue

Alkaline-based aqueous batteries have attracted intensive research interests due to their high voltage, low cost, and high safety. However, metal anodes in alkaline electrolytes usually possess poor stability and severe side reactions. Organics are potential alternatives to address these problems, but they are typically not negative enough as anodes. Herein, a group of organic phenazine derivatives including phenazine (PZ), 2-hydroxyphenazine (PZ-OH), and 1,2-dihydroxyphenazine (PZ-2OH) are developed as anode materials for alkaline-based batteries. It is revealed that introducing hydroxyl groups can lower the redox potential by 0.4 V, and fast ion transport channels formed by intramolecular hydrogen bonds can remarkably improve redox kinetics. The optimized PZ-2OH‖Ni (OH)2 batteries deliver a high capacity of 208 mA h g−1anode, a high energy density of 247 W h kg−1anode, and ultra-stable cyclability …

Chlorine-based electrochemical energy storage is a promising candidate for sustainable battery technology. The anionic redox reaction of Cl0/−1 is of interest due to its superior redox potential (1.36 V vs. standard hydrogen electrode [SHE]), capacity (756 mAh g−1), high power, and low cost. Although Cl chemistry has been used in aqueous batteries for a long time, its deployment in organic lithium batteries has been significantly impeded due to the insolubility of Cl− ions (<0.1 M). Scarce oxidizable Cl− blocks redox reactions and the inevitable lithium chloride (LiCl) film passivates electrodes on discharge. We report a eutectic effect to improve the Cl− solubility in organic electrolytes (2 M or higher) by mixing a series of N-/P-centered chloride salts with lithium bis(trifluoromethanesulfonyl)imide at specific ratios. Based on an optimized Cl− concentration, a Li-Cl2 cell using I as a chemical fixation can achieve a three …

Chlorine‐based batteries with Cl0 to Cl− redox reaction (ClRR) are promising for high‐performance energystorage due to their high redox potential and large theoretical capacity. However, the inherent gas–liquid conversion feature of ClRR together with poor Cl fixation can cause Cl2 leakage, reducing battery reversibility. Herein, we utilize a Se‐based organic molecule, diphenyl diselenide (di‐Ph‐Se), as the Cl anchoring agent and realize an atomic level‐Cl fixation through chalcogen‐halogencoordinating chemistry. The promoted Cl fixation, with two oxidized Cl0 anchoring on a single Ph‐Se, and the multivalence conversion of Se contributeto a six‐electron conversion process with up to 507 mAh g−1 and an average voltage of 1.51 V, as well as a high energy density of 665 Wh Kg−1. Based on the superior reversibility of thedeveloped di‐Ph‐Se electrode with ClRR, a remarkable rate performance (205 mAh g …

Anionic redox reactions would achieve a higher capacity than typical transition-metal-oxide cathodes, offering low-cost chemistry for advanced lithium-ion batteries. Li-Cl2 chemistry using anionic redox reactions of Cl0/−1 shows superior operation voltage (∼3.8 V) and capacity (756 mAh g−1). However, a redox-active and reversible chlorine cathode has not been developed in organic electrolyte-based lithium-ion batteries. Chlorine ions bonded by ionic bonding hardly dissolve in organic electrolytes, imposing a thermodynamic barrier for redox reactions. Meanwhile, chlorine gas is easily formed during oxidation. Herein, we report an interhalogen compound, iodine trichloride (ICl3), as the cathode to address these two issues. In situ and ex situ spectroscopy data and calculations reveal that reduced Cl− ions are partially dissolved in the electrolyte, and oxidized Cl0 is anchored by forming interhalogen bonds. A …

Polymer blends based solid polymer electrolytes (SPEs), combining the advantages of multiple polymers, are promising for the utilization of 5 V‐class cathodes (e.g., LiCoMnO4 (LCMO)) with enhanced safety. However, severe macro‐phase separation with defects and voids in polymer blends restrict the electrochemical stability and ionic migration of SPEs. Herein, inorganic compatibilizer polyacrylonitrile grafted MXene (MXene‐g‐PAN) is exploited to improve the miscibility of the poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVHF)/PAN blends and suppress the consolidation of phase particles. The resulting SPE exhibits a high anodic stability with an ionic conductivity of 2.17 × 10−4 S cm−1, enabling a stable and reversible Li platting/stripping (over 2500 h). The fabricated solid Li‖LCMO cell delivers a 5.1 V discharge voltage with a decent capacity (131 mAh g−1) and cycling performance. Subsequently …

Chalcogens, especially tellurium (Te), as conversion-type cathodes possess promising prospects for zinc batteries (ZBs) with potential rich valence supply and high energy density. However, the conversion reaction of Te is normally restricted to the Te2–/Te0 redox with a low voltage plateau at ∼0.59 V (vs Zn2+/Zn) rather than the expected positive valence conversion of Te0 to Ten+, inhibiting the development of Te-based batteries toward high output voltage and energy density. Herein, the desired reversible Te2–/Te0/Te2+/Te4+ redox behavior with up to six-electron transfer was successfully activated by employing a highly concentrated Cl–-containing electrolyte (Cl– as strong nucleophile) for the first time. Three flat discharge plateaus located at 1.24, 0.77, and 0.51 V, respectively, are attained with a total capacity of 802.7 mAh g–1. Furthermore, to improve the stability of Ten+ products and enhance the cycling …

A separator for a battery contains a MXene nanosheet, a poly (vinylidene fluoride-co-hexafluoropropylene) framework, and a physical isolation flame retardant dispersed within the poly (vinylidene fluoride-co-hexafluoropropylene) framework. The MXene nanosheet is affixed to the poly (vinylidene fluoride-co-hexafluoropropylene) framework. A separator manufacturing method for the separator herein and a battery manufacturing method are also included.

The operating temperature of batteries is an essential consideration in actual applications. Understanding the temperature dependence is conducive to battery design. The experience in lithium-ion batteries (LIBs) indicates that the dendrite issue is exacerbated at lower temperatures and suppressed at higher temperatures. In this study, we revealed the dendrite evolution in aqueous rechargeable zinc-based batteries (RZBs), for which the opposite temperature dependence was observed. Detailed investigations elucidate that the degree of matching of the interface reaction rate and ion diffusivity, together with side reactions, are the key factors that determine the cycling performance. The different properties of organic and aqueous electrolytes result in a reversed temperature dependence. We further conducted a detailed investigation of hybrid electrolytes (organic and aqueous) for balancing the ion diffusivity and …

Metal hexacyanoferrates are recognized as superior cathode materials for zinc and zinc hybrid batteries, particularly the Prussian blue analog (PBA). However, PBA development is hindered by several limitations, including small capacities (<70 mAh g−1) and short lifespans (<1000 cycles). These limitations generally arise due to incomplete activation of redox sites and structure collapse during intercalation/deintercalation of metal ions in PBAs. According to this study, the adoption of a hydroxyl‐rich (OH‐rich) hydrogel electrolyte with extended electrochemical stability windows (ESWs) can effectively activate the redox site of low‐spin Fe of the KxFeyMn1−y[Fe(CN)6]w·zH2O (KFeMnHCF) cathode while tuning its structure. Additionally, the strong adhesion of the hydrogel electrolyte inhibits KFeMnHCF particles from falling off the cathode and dissolving. The easy desolvation of metal ions in the developed OH‐rich …

Most current research is devoted to electrochemical nitrate reduction reaction for ammonia synthesis under alkaline/neutral media while the investigation of nitrate reduction under acidic conditions is rarely reported. In this work, we demonstrate the potential of TiO2 nanosheet with intrinsically poor hydrogen-evolution activity for selective and rapid nitrate reduction to ammonia under acidic conditions. Hybridized with iron phthalocyanine, the resulting catalyst displays remarkably improved efficiency toward ammonia formation owing to the enhanced nitrate adsorption, suppressed hydrogen evolution and lowered energy barrier for the rate-determining step. Then, an alkaline-acid hybrid Zn-nitrate battery was developed with high open-circuit voltage of 1.99 V and power density of 91.4 mW cm–2. Further, the environmental sulfur recovery can be powered by above hybrid battery and the hydrazine-nitrate fuel cell …

Highly reversible Zn–air batteries (ZABs) in near-neutral aqueous electrolytes can suppress the formation of Zn dendrites and carbonates. However, near-neutral ZABs (NNZABs) based on Zn peroxide (ZnO2) chemistry are challenging to build due to the air circulation requirement and the Swagelok structure. To achieve cost-effective NNZABs in a coin-cell configuration, it is essential to explore air-breathing cathodes with high catalytic activity for near-neutral systems. Previous studies focused on catalysts for alkaline ZABs, which are usually not suitable for near-neutral batteries. Here, Mo4/3B2−xTz MBene with ordered vacancies is for the first time exploited as a high-performance catalyst for NNZABs. Interestingly, a stable lifecycle for 380 h under a current density of 2 mA cm−2 and a 5 h cycling period was achieved, which is attributed to the high O2-adsorbability and air stock capacity of Mo4/3B2−xTz MBene. We …

Due to the high abundance of their components, low cost, and high safety, zinc‐based batteries open up new vistas for large‐scale energy storage. However, their stability, lifetime, and reversibility are impaired by passivation and dendrite growth of the Zn anode. Here, this challenge is circumvented by an iodine post‐functionalized zeolitic imidazolate framework‐90 (ZIF‐90‐I) additive, in which the polycation absorbed on Zn anode can regulate solid–electrolyte interphase (SEI) formation in the 1 m Zn(TFSI)2 electrolyte and induce Zn2+ uniform deposition. Moreover, the I3−/I− redox can rejuvenate dead Zn and inhibit dendrites. With the ZIF‐90‐I additive, Zn plating/stripping at 99.5% Coulombic efficiency for 120 cycles is obtained in Zn||Ti cells at 20 mA cm−2/1 mAh cm−2. In addition, Zn||Zn cells show steady cycling for 1200 h at 5 mA cm−2/1 mAh cm−2 with stable overpotentials. The utilization rate of Zn reaches …

Uncontrollable dendrite formation in the Zn anode is the bottleneck of the commercialization of rechargeable aqueous zinc-based batteries (RAZBs). Interface, the location of the charge transfer process occuring, can significantly affect the further morphology evolution in ways that have not yet been fully comprehended, for example, the crystal facet and orientation of the coating layer. In this study, we demonstrated that the morphology and kinetics of the Zn anode could be tuned by the crystal facet. The fabricated textured ZnSe (T-ZnSe) layer can significantly enhance the reaction kinetics and induce uniform (0002)Zn deposition. In stark contrast, the polycrystalline P-ZnSe coating hinders the charge transfer process at the interface. With this T-ZnSe@Zn as the anode, the full cell with an I2 cathode and a practical areal capacity (2 mAh cm–2) can work well for 900 cycles. The effectiveness of this anode has also been …

Electrolyte environments, including cations, anions, and solvents are critical for the performance delivery of cathodes of batteries. Most works focused on interactions between cations and cathode materials, in contrast, there is a lack of in‐depth research on the correlation between anions and cathodes. Here, we systematically investigated how anions manipulate the coulombic efficiency (CE) of cathodes of zinc batteries. We take intercalation‐type V2O5 and conversion‐type I2 cathodes as typical cases for profound studies. It was found that electronic properties of anions, including charge density and its distribution, can tune conversion or intercalation reactions, leading to significant CE differences. Using operando visual Raman microscopy and theoretical simulations, we confirm that competitive coordination between anions and I− can regulate CEs by modulating polyiodide diffusion rates in Zn−I2 cells. In Zn−V2 …

Metal–organic framework‐based materials are promising single‐site catalysts for electrocatalytic nitrate (NO3−) reduction to value‐added ammonia (NH3) on account of well‐defined structures and functional tunability but still lack a molecular‐level understanding for designing the high‐efficient catalysts. Here, we proposed a molecular engineering strategy to enhance electrochemical NO3−‐to‐NH3 conversion by introducing the carbonyl groups into 1,2,4,5‐tetraaminobenzene (BTA) based metal‐organic polymer to precisely modulate the electronic state of metal centers. Due to the electron‐withdrawing properties of the carbonyl group, metal centers can be converted to an electron‐deficient state, fascinating the NO3− adsorption and promoting continuous hydrogenation reactions to produce NH3. Compared to CuBTA with a low NO3−‐to‐NH3 conversion efficiency of 85.1 %, quinone group functionalization …

Among the promising batteries for electric vehicles, rechargeable Li‐air (O2) batteries (LABs) have risen keen interest due to their high energy density. However, safety issues of conventional nonaqueous electrolytes remain the bottleneck of practical implementation of LABs. Solid‐state electrolytes (SSEs) with non‐flammable and eco‐friendly properties are expected to alleviate their safety concerns, which have become a research focus in the research field of LABs. Herein, we present a systematic review on the progress of SSEs for rechargeable LABs, mainly focusing on the interfacial issues existing between the SSEs and electrodes. The discussion highlights the challenges and feasible strategies for designing suitable SSEs for LABs.

The development of flexible lithium‐ion batteries (LIBs) imposes demands on energy density and high mechanical durability simultaneously. Due to the limited deformability of electrodes, as well as the flat and smooth surface of the metal current collectors, stable/durable/reliable contact between electrode materials and the current collectors remains a challenge, in particular, for electrodes with high loading mass and heavily deformed batteries. Binders play an essential role in binding particles of electrode materials and adhering them to current collectors. Herein, inspired by spider silk, a binder for flexible LIBs is developed, which equips a cross‐linked supramolecular poly(urethane‐urea) to the polyacrylic acid. The binder imparts super high elastic restorability originating from the meticulously engineered hydrogen‐bonding segments as well as extraordinary adhesion. The developed binder provides excellent …

Chalcogens undergoing positive valence conversions show great potential to achieve a high discharge voltage in batteries; however, such reactions with high reversibility are difficult to achieve because element O/S/Se are inherently electron acceptors. Herein, by incorporating the chalcogens with the unique triphenylphosphine-based structure (strong electron-withdrawing groups), a high-potential triphenylphosphine selenide organic cathode (TP-Se) is developed. Facilitated by a Zn2+/trifluoromethanesulfonate (OTF−) hosting mechanism, the (TP-Se)− to (TP-Se)0 to (TP-Se)+ conversion is realized. The dual-ion Zn‖TP-Se batteries exhibit a flat discharge plateau at 1.96 V and a superior discharge capacity. Benefiting from the stable triphenylphosphine molecular structures and optimized hybrid electrolytes, excellent cycling performance is also attained (up to 85.3% capacity retention after 4,300 cycles …

Dendrite-free lithium-ion batteries (LIBs) are usually achieved by constructing an artificial SEI layer on Li anode, inevitable to be performed in harsh operating condition and bring barriers to quantity production. This issue can be relieved by designing multifunctional separators with Li deposition tunability. Herein, the MXene on a developed separator plays a crucial role in controlling the deposition configuration of Li metal and hindering the internal short circuits caused by ununiform Li dendrites growth. Furthermore, the developed separator based on the poly (vinylidene fluoride-co-hexafluoropropylene) (abbreviated as PVHF) filled by the hydroxyapatite nanowire networks (abbreviated as HAP) and decorated with MXene (denoted as M-HAP@PVHF) displays superior safety performance than the conventional polypropylene (denoted as PP) separator under the same flame-resistance testing condition. The M-HAP …

Rechargeable lithium–iodine batteries are highly attractive energy storage systems featuring high energy density, superior power density, sustainability, and affordability owing to the promising redox chemistries of iodine. However, severe thermodynamic instability and shuttling issues of the cathode have plagued the active iodine loading, capacity retention and cyclability. Here the development of highly thermally and electrochemically stable I−/I3−‐bonded organic salts as cathode materials for Li–I2 batteries is reported. The chemical bonding of iodine/polyiodide ions with organic groups allows up to 80 wt% iodine to be effectively stabilized without sacrificing fast and reversible redox reaction activity. Thus, the shuttle effect is significantly inhibited, which improves cathode capacity and restrains side‐reactions on the Li anode. As a result, such cathodes afford Li–I2 batteries a specific capacity of 173.6 mAh g−1 …