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Lithium–sulfur (Li−S) battery with a sulfurized polyacrylonitrile cathode is a promising alternative to Li‐ion systems. However, the sluggish charge transfer of cathode and accumulation of inactive Li on anode remain persistent challenges. An advanced electrolyte additive with function towards both cathode and anode holds great promise to address these issues. Herein, we present a new strategy to boost sulfur activity and rejuvenate dead Li simultaneously. In the polar electrolyte containing I2−LiNO3 additives, I3−/IO3− are triggered significantly by the reaction between NO3− and I− ions. The I3−/IO3− are reactive to insulated Li2S product of cathode and inactive Li on anode, thus accelerating the conversion reaction of sulfur and recovering Li sources back to battery cycling. The in situ/ex situ spectroscopic and morphologic monitoring reveal the crucial role of iodine in promoting Li2S dissociation and inhibiting dendritic Li growth. With the modified electrolyte, the symmetric Li||Li cells deliver a lifespan of 4000 h with an overpotential less than 12 mV at 0.5 mA cm−2. For Li−S cells, 100 % capacity retention up to thousands of cycles and enhanced rate capability are available. This work demonstrates a feasible strategy on electrolyte engineering for practical applications of Li−S batteries. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries (SIBs), based on hard carbon anodes and Na+‐intercalation compound cathodes, have gained significant attention. Nonetheless, hard carbon anodes involve the storage of Na+ at a low potential, typically below 0.1 V (vs Na/Na+), which increases the risk of dendritic Na growth on the anode surface during overcharging. Herein, a safe organic/inorganic composite anode containing tetrasodium 3,4,9,10‐perylenetetracarboxylate (Na4PTC) and Metallic bismuth (Bi) with a weight ratio of 7:2, which exhibits an average potential of 0.7 V (vs Na+/Na) and a capacity of 150 mAh g−1 is proposed. The electrode reaction involves a reversible coordination reaction within the organic host and alloying reactions within the metallic Bi component. Importantly, the organic component efficiently buffers the volume changes in Bi during the alloying reaction, while the metallic Bi enhances the electronic conductivity of the organic material. As a result, this composite anode shows high cycle stability and rate performance, even under high mass loadings ranging from 10 to 50 mg cm−2. Furthermore, it is demonstrated that the Na‐ion full cell, consisting of the composite anode and the Na3V2O2(PO4)2F cathode, exhibits minimal capacity degradation over 100 cycles while maintaining a high areal capacity of 1.1 mA cm−2. [ABSTRACT FROM AUTHOR]

O3‐type layered oxides are promising cathode materials for sodium‐ion batteries. However, unsatisfying cyclic stability hinders its practical application, mainly resulting from harmful phase transition and irreversible oxygen redox, especially in high‐voltage regions. Herein, a co‐doped strategy by incorporating Li+, Mg2+, Ca2+, and Sb5+ into the O3‐Na0.8Ni0.4Fe0.2Mn0.4O2 cathode materials is proposed. Both suppressing the undesired phase transition over 4.1 V (vs Na/Na+) and reducing the anisotropic strain are achieved with the novel Na0.8Ni0.3Fe0.2Mn0.3Li0.1Mg0.02Ca0.05Sb0.03O2 (LMCS NFM). Moreover, restricted but highly reversible oxygen redox is observed due to strong attraction from Sb5+ and special "Li–O‐vacancy" and "Mg–O‐vacancy" configurations. The strategy brings about excellent high‐voltage cyclic stability with a reversible capacity of 130 mAh g−1 and a capacity retention of 85% after 250 cycles at 4.2 V, and less thermal runaway risk and moisture sensitivity, increasing the probability of O3‐type oxide cathode practical applications. [ABSTRACT FROM AUTHOR]

Oxygen deficiency has crucial effects on the crystal structure and electrochemical performance of spinel oxide lithium electrode materials such as LiNi0.5Mn1.5O4 (LNMO) cathode. In particular, the oxygen stoichiometry on the crystal surface differs from that on the crystal interior in LNMO. The detection of local oxygen loss in LNMO and its correlation with the crystal structure and the cycling stability of LNMO remain challenging. In this study, the effect of oxygen deficiency in LNMO controlled by sintering temperature on the surface crystal structure and electrochemical performance of LNMO is comprehensively investigated. The high concentration of oxygen vacancies segregates at the surface regions of LNMO forming a thin rock‐salt and/or deficient spinel surface layer. The atomic‐level surface structure reconstruction was demonstrated by annular dark‐field and annular bright‐field techniques. For the synthesis of LNMO, the higher sintering temperature results in higher crystallinity but the higher oxygen deficiency in LNMO. The high crystallinity of LNMO would increase the thermal stability of LNMO cathodes while the high content of oxygen deficiency would decrease the surface structural stability of LNMO. Therefore, the LNMO sintered at a medium temperature of 850°C achieved the best capacity retention. The results suggest a competitive function mechanism between oxygen stoichiometry and the crystallinity of LNMO on the cycling performance of LNMO. [ABSTRACT FROM AUTHOR]

Polyaniline is the most famous conducting polymer and also a promising organic cathode material for rechargeable batteries, however, it has demonstrated poor utilization of its theoretical capacity (294 mAh g−1) and inferior cycling stability in previous studies. Herein, for the first time, its fully reduced form, i.e., leucoemeraldine base (LB), is studied as an alternative to the commonly used emeraldine salt and base (ES and EB). For the three different forms, the precise structures are carefully determined, and the electrochemical performance are systematically investigated. Within 2.0−4.3 V, LB realizes almost full capacity utilization (92%) that is much superior to those of ES and EB. Within 2.0−4.2 V, it shows both high reversible capacity (277 mAh g−1) and cycling stability (84% capacity retention after 1000 cycles). The combination of electrochemical analysis, density functional theory calculation, and ex situ characterization reveals that the capacity utilization is positively associated with the pristine proportion of ─NH─ groups, and the capacity fading is caused by the irreversible electrochemical deprotonation at high charge potential. This work promotes both the electrochemical performance and mechanistic understanding of polyaniline to a new stage, towards practical application in energy storage devices as a low‐cost, high‐performance, sustainable, and green cathode material. [ABSTRACT FROM AUTHOR]

Organic p‐type cathode materials have recently attracted increasing attention due to their higher redox potentials and rate capabilities in comparison to n‐type cathodes. However, most of the p‐type cathodes based on one‐electron redox still suffer from limited stability and low specific capacity (<150 mAh g−1). Herein, two polymers, conjugated poly(diethyldihydrophenazine vinylene) (CPP) and non‐conjugated poly(diethyldihydrophenazine ethylidene) (NCPP) containing two‐electron redox dihydrophenazine, have been developed as p‐type cathode materials. It is experimentally and theoretically found that the conjugated linkage among the redox centers in polymer CPP is more favorable for the effective charge delocalization on the conjugated polymer backbone and the sufficient oxidation in the higher potential region (3.3–4.2 V vs. Li/Li+). Consequently, the CPP cathode displays a higher reversible specific capacity of 184 mAh g−1 with excellent cycling stability. [ABSTRACT FROM AUTHOR]

Aqueous Zn‐organic batteries have received considerable attention owing to their green, low‐cost and high safe nature. Unfortunately, organic materials generally exhibit insulator nature (≈10−10 S cm−1), and most of reported promising performances of Zn‐organic batteries are achieved with a low mass‐loading (≈2 mg cm−2) in cathode, which is far away from practical application (10 mg cm−2). Herein, we demonstrate a semi‐conductive polymer poly(1,8‐diaminonaphthalene) (PDAN) cathode material for Zn batteries, which shows a moderate electronic conductivity (5.9×10−5 S cm−1). Theoretical calculations and in situ/ex situ analysis reveal that the cathode involves a bipolar‐type charge storage mechanism. Accordingly, the Zn//PDAN cell exhibits a promising capacity (140 mAh g−1 at 0.1 A g−1) and a remarkable cycle stability (1000 cycles without capacity fading) at a high mass‐loading (10 mg cm−2). These encouraging results shed light on the design of advanced organic electrode. [ABSTRACT FROM AUTHOR]

Proton batteries are emerging in electrochemical energy storage because of the associated fast kinetics, low cost and high safety. However, their development is hindered by the relatively low energy density due to the limited choice of cathode materials. Herein, metal phosphate polyanion cathodes are proposed as the proton cathode for the first time. Combining experimental results and theoretical simulations, a universal criterion for the proton cathode was put forward. Vanadium fluorophosphate (VPO4F) was demonstrated as a promising high‐voltage proton cathode material with a specific capacity of 116 mAh g−1 at a high potential of 1.0 V (vs. SHE). The proton insertion/extraction mechanism in the VPO4F electrode was also verified through X‐ray diffraction (XRD) and photoelectron spectroscopy (XPS). Furthermore, the stability of VPO4F was investigated in various electrolytes and the optimized electrolyte enabled the stable operation of VPO4F for 300 cycles. This work provides new inspiration in the exploitation of new electrode materials for electrochemical proton storage devices. [ABSTRACT FROM AUTHOR]

Energy and environmental issues have given rise to the development of advanced energy‐storage devices worldwide. Electrochemical energy technologies, such as rechargeable batteries, are considered to be the most reliable and efficient candidates. Compared with other batteries, zinc‐based batteries seem promising due to their advantages, including inherent safety, cost‐effectiveness, and environmentally friendliness. As potential alternatives to conventional inorganic cathodes, organic cathodes for Zn–organic batteries have become a hot topic for research, owing to their favorable characteristics, such as easy structure design, controllable synthesis, and environmental benignancy. Herein, a systematic overview on the fundamentals of organic cathode materials for zinc batteries, including material design, electrochemical mechanisms, technical advances, and challenging analysis, is provided. Furthermore, perspectives and corresponding research directions are offered to facilitate the future development of organic cathode materials for zinc batteries toward practical applications. [ABSTRACT FROM AUTHOR]

Abstract: Rechargeable batteries have been used to power various electric devices and store energy from renewables, but their toxic components (namely, electrode materials, electrolyte, and separator) generally cause serious environment issues when disused. Such toxicity characteristic makes them difficult to power future wearable electronic devices. Now an environmentally friendly and highly safe rechargeable battery, based on a pyrene‐4,5,9,10‐tetraone (PTO) cathode and zinc anode in mild aqueous electrolyte is presented. The PTO‐cathode shows a high specific capacity (336 mAh g−1) for Zn2+ storage with fast kinetics and high reversibility. Thus, the PTO//Zn full cell exhibits a high energy density (186.7 Wh kg−1), supercapacitor‐like power behavior and long‐term lifespan (over 1000 cycles). Moreover, a belt‐shaped PTO//Zn battery with robust mechanical durability and remarkable flexibility is first fabricated to clarify its potential application in wearable electronic devices. [ABSTRACT FROM AUTHOR]

Lithium (Li)-rich layered oxides are considered promising cathode materials for Li-ion batteries because of their favorable properties. Here, we report our recent finding in the novel oxide, aluminum fluoride (AlF 3 )-modified Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (LMNCAF), which was synthesized via a facile, cost-effective and readily scalable solid-state reaction. LMNCAF possess an F and Al co-doped core structure with a LiF nano-coating on its surface which leads to considerably enhancement in the electrochemical performance of the oxide. The initial discharge capacity (at 0.05 C) increased from 212 mA h g −1 for Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 to 291 mA h g −1 for LMNCAF. A much higher discharge capacity of 211 mA h g −1 was obtained for LMNCAF after 99 charge/discharge cycles at 0.2 C compared with that of Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (160 mA h g −1 ). Our preliminary results suggest that AlF 3 modification is an effective strategy to tailor the physicochemical and electrochemical properties of Li-rich layered oxides. [ABSTRACT FROM AUTHOR]

A newly designed hybrid separator composed of a glassy fiber paper and a microporous membrane is effectively integrated into a Li–S battery. Superior cell performance up to 500 cycles is achieved even with commercially available pristine sulfur as cathode material. This fascinating study demonstrates a largely restrained polysulfides shuttle process toward practical Li–S battery application. [ABSTRACT FROM AUTHOR]

Building a low-carbon society supported by sustainable energy is a worldwide topic. The aqueous lithium-ion battery (LIB) has been demonstrated to be one of the most promising stationary power sources for sustainable energies such as wind and solar power. The aqueous LIB may solve both the safety problem associated with the lithium-ion batteries which use highly toxic and flammable organic solvents, and the poor cycling life associated with commercialized aqueous rechargeable batteries including lead-acid and nickel-metal-hydride systems. During the past decades, many efforts have been made to improve the performance of the aqueous lithium-ion battery. The present work reviews the latest advances in the exploration and development of battery systems and relative materials. Also the main approaches, achievements, and challenges in this field are briefly commented on and discussed. [ABSTRACT FROM AUTHOR]

Abstract: One-dimensional (1D) nanorods of LiV3O8 single crystals have been fabricated by using well-defined home-made VO2 (B) nanorods as the vanadium resource, combined with a convenient solid-state reaction. The as-obtained LiV3O8 nanorods were characterized by XRD, TEM and SEM, indicating this material was highly crystalline and a single phase. The electrochemical performance of LiV3O8 nanorods as the positive electrode material for rechargeable lithium batteries was investigated, which demonstrated that as-prepared LiV3O8 nanorods exhibited as high as 348mAhg−1 discharge capacity in first cycle at 20mAg−1 current density, and still remained at 303mAhg−1 at 50mAg−1 afterwards; moreover, until 50 cycles, they kept 315mAhg−1, recorded at 50mAg−1. All these results imply that single-crystalline 1D nanorods of LiV3O8 are promising cathode material for rechargeable lithium batteries. [Copyright &y& Elsevier]

S 0.87 Se 0.13 /CPAN (carbonized polyacrylonitrile) composites material was synthesized by annealing the mixture of S (sulfur), Se (selenium) and PAN directly at 400 °C. The prepared composites was used as high capacity and stable cycling performance cathode for lithium sulfur battery. It delivers a specific capacity of 1210 mAh g −1 after 100 cycles at a constant current density of 120 mA g −1 . In addition, it remains 989 mAh g −1 after 200 cycles at a current density of 300 mA g −1 with ultralow capacity fading of 0.025% per cycle. Meantime, the S 0.87 Se 0.13 /CPAN cathode exhibits extremely low self-discharge behavior. The superior electrochemical performance of S 0.87 Se 0.13 /CPAN composites should be ascribed to high S/Se ratio in S 0.87 Se 0.13 /CPAN composites and good conductivity brought by the addition of Se, which make full use of high capacity of S. Moreover, the chemical bonding between Se and S, as well as the chemical bonding between S 0.87 Se 0.13 and CPAN decrease the loss of active material. This easy one-step synthesis procedure offers a feasible new route for the development of sulfide-based cathode material. [ABSTRACT FROM AUTHOR]

Li-rich layered oxides are promising cathode materials for advanced Li-ion batteries because of their high specific capacity and operating potential. In this work, the Li-rich layered oxide Li 1·2 Mn 0·54 Ni 0·13 Co 0·13 O 2 (LMNC), is modified via a carbonization-reduction process (yielding the corresponding reduced compound denoted LMNC-R). Compared to the pristine oxide, LMNC-R delivers significantly enhanced initial discharge capacity/columbic efficiency, remarkably improved rate performance with an accelerated Li + diffusion rate, and significantly increased capacity/voltage retention. The specific energy density and energy retention after 100 cycles increase from 378.2 Wh kg −1 and 47.7% for LMNC to 572.0 Wh kg −1 and 71.3%, respectively, for LMNC-R. The enhancement in the electrochemical performance of LMNC-R can be attributed to the synchronous formation of the oxygen non-stoichiometric Li 2 MnO 3-δ component and to the carbon/spinel double coating layer in the material that resulted from the post-treatment process. Thus, the carbonization-reduction modification process can be used to tailor the structural evolution procedure and to suppress the metal ion dissolution of the Li-rich layered oxide during cycling. [ABSTRACT FROM AUTHOR]

[Display omitted] Aqueous Na-ion batteries have been extensively studied for large-scale energy storage systems. However, their wide application is still limited by their inferior cycle stability (<3000 cycles) and poor temperature tolerance. Furthermore, many of the reported high rate behaviors are achieved at a low mass loading (<3 mg cm−2) of the electrodes. Herein, we propose an aqueous Na-ion battery which includes a Ni-based Prussian blue (NiHCF) cathode, a carbonyl-based organic compound, 5,7,12,14-pentacenetetrone (PT) anode and a "water-in-salt" electrolyte (17 mol kg−1 NaClO 4 in water). Its operation involves the reversible coordination reaction of the PT anode and the extraction/insertion of Na+ in the NiHCF cathode. It is demonstrated that the wide internal spaces of the PT anode and NiHCF cathode can not only buffer the volumetric change induced by Na+ storage, but also enable fast kinetics. The full cell exhibits a supercapacitor-like rate performance of 50 A g−1 (corresponding to a discharge or charge within 6.3 s) and a super-long lifespan of 15,000 cycles. Moreover, the excellent rate performance can still be preserved even with a high mass loading of the electrodes (15 mg NiHCF cm−2 and 8 mg PT cm−2). Especially, the cell can work well in a wide temperature range, from −40 to 100 °C, showing a typical all-climate operation. [ABSTRACT FROM AUTHOR]

• Sulfurized poly(o-phenylenediamine) (SPoPDA) is a novel cathode for Li–S batteries. • SPoPDA can realize the highest content of covalently bonded sulfur (∼60 wt%). • SPoPDA can realize the solid-phase conversion of sulfur with ester-type electrolyte. • SPoPDA shows a reversible capacity of 589 mAh g−1 and stable cycling of 100 cycles. • The redox mechanisms of sulfurized polymers have been quantitatively revealed. The combination of sulfurized polymer cathode and ester-type electrolyte can realize the solid-phase conversion of sulfur cathode, which is a promising solution of the dissolution issue of Li–S batteries. In this regard, sulfurized polyacrylonitrile (SPAN) is the most famous material and few attempts have been made to challenge it in the past two decades. Herein, we report sulfurized poly(o-phenylenediamine) (SPoPDA) as its supplement or alternative for rechargeable lithium batteries. Compared with SPAN, SPoPDA shows higher ability to covalently bond with sulfur (from ∼50 to ∼60 wt%), similar reversible capacity (∼600 mAh g−1), better cycling stability (with only 2% loss of charge capacity during 100 cycles), and faster reaction kinetics. The molecular structures and electrochemical reaction mechanisms of them have been quantitatively analyzed, and the electrode structure variation of SPoPDA during discharge–charge process has been thoroughly investigated. This work provides not only a novel sulfurized polymer cathode material with low cost, easy synthesis, and high electrochemical performance, but also clearer mechanism understanding of solid-phase conversion sulfur cathode, which are of significant importance for the development of Li–S batteries towards practical application. [ABSTRACT FROM AUTHOR]

[Display omitted] • The morphology–property relationship of SPAN is established. • The SPAN with large fragments in ether electrolyte triggers polysulfide shuttling. • The soluble polysulfides may generate from SPAN by breaking −S−S x −S− bonds. • The disproportion reaction of Li 2 S with −S x − clusters also produces polysulfides. • The rearrangement of SPAN is rationally utilized to prompt its reaction kinetics. Sulfurized polyacrylonitrile (SPAN) is one of the most promising cathode materials with high energy density. However, irreversible shuttling effect is easily triggered by formation of soluble polysulfides (Li 2 S n , 2< n ≤8) in ether electrolytes. The major challenge relies in the control of molecular rearrangement of SPAN to avoid spontaneous generation of Li 2 S n. This work reveals the morphological and structural roles that responsible for the compatibility of SPAN with ether electrolytes. Besides the length of the covalently bonded –S x – chains in the pyrolyzed PAN backbone, the protection of SPAN fragments from robust interactions with solvents enables a stable cycling of electrodes. The freestanding SPAN cathode with a continuous fibrous network exhibits a much higher electrochemical stability than its powder counterparts. The single-phase solid-solid reaction of SPAN with Li+ can be realized with Li 2 S as the sole discharge product. Nevertheless, the reversible reaction is kinetically dominated by the activation of the produced Li 2 S. The recharge ability and rate capability can be improved by rationally controlling the molecular rearrangement of SPAN. The trace amount of in-situ generated Li 2 S n acting as a chemical mediator can promote the reversible decomposition of Li 2 S, offering a new insight into cathode design of Li–S batteries. [ABSTRACT FROM AUTHOR]

Graphical abstract RuO 2 -CNTs@Li anode is coupled with RuO 2 -CNTs cathode to construct a Li−O 2 full cell with ultrahigh energy density and excellent rechargeability. Abstract The intense interest of Li–O 2 battery stems from its ultrahigh theoretical energy density, but its application is still hindered by the issues of Li anode. Herein, RuO 2 -CNTs composite, a conventional O 2 cathode catalyst in Li–O 2 battery, is first utilized as an anode host for dendrite-free Li plating/stripping with high Coulombic efficiency. It is demonstrated that such excellent plating/stripping performance arises from the lithiophilicity characteristic of Ru nanoparticles (that is derived from the in-situ electrochemical conversion from RuO 2 to Ru/Li 2 O) and buffer space provided by CNTs. Furthermore, the RuO 2 -CNTs electrode pre-deposited with limited Li (RuO 2 -CNTs@Li anode) is coupled with a RuO 2 -CNTs catalytic cathode to form a Li–O 2 full cell, which displays an extended cycle life with dramatically improved energy density. The achieved cell shows a high stability of 200 cycles with RuO 2 -CNTs@Li anode (1 mg Li) that sheds light on the efficient utilization of Li anode in Li–O 2 batteries. [ABSTRACT FROM AUTHOR]

Abstract Na 2+2x Fe 2-x (SO 4) 3 is considered a promising cathode material for advanced sodium ion batteries with higher energy density due to its advantage of high-voltage, earth-abundant elements material and low-cost. However, strongly impeded by its fatal environmental sensitivity and low electronic conductivity, the NFS usually shows unsatisfactory electrochemical performance. Herein, a facile synthesis of microspherical NFS@reduced graphene oxide composites are synthesized through spray-drying method. The well-designed microspherical NFS@rGO with confined NFS nanocrystal in the three-dimensional graphene framework exhibits superb electronic and ionic conductivity as well as structural stability. The NFS@rGO composites show outstanding electrochemical properties: high sodium storage capacity (99 mAh g−1 at 0.1 C), superior rate performance (78 mAh g−1 at 60 C and even up to 72 mAh g−1 at 80 C), ultralong cycling stability (80.8% capacity retention after 2000 cycles at 30 C). The excellent performance makes the NFS@rGO material a prospective electrode candidate for large-scale SIBs. Graphical abstract Image 1 Highlights • The NFS@rGO was successfully prepared through a facile spray-drying method. • The robust 3D graphene skeleton ensures NFS@rGO structural stability. • The 3D highly conductive graphene network boost the electronic conductivity. • The NFS@rGO demonstrates ultrafast and ultralong-term cycling. [ABSTRACT FROM AUTHOR]

The effect of calcium on the properties of SmBa 1–x Ca x CoCuO 5+δ (x = 0.0–0.3) as a cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs) is evaluated systematically. Samples exhibit a highly crystalline double perovskite phase, and their cell volumes decrease as x is changed from 0.0 to 0.3. The oxygen content and average thermal expansion coefficient (TEC) of SmBa 1–x Ca x CoCuO 5+δ decreases as the calcium content increased. An average TEC of as low as 15.3 × 10 −6 °C −1 is obtained for SmBa 0.7 Ca 0.3 CoCuO 5+δ . The area specific resistances at 700 °C decrease by approximately 50% when the calcium content is increased from x = 0.0 (0.173 Ω cm 2 ) to x = 0.3 (0.086 Ω cm 2 ). The maximum power densities of SmBa 1−x Ca x CoCuO 5+δ -based single cells at 800 °C increase from 635 mW cm −2 (x = 0.0) to 939 mW cm −2 (x = 0.3). [ABSTRACT FROM AUTHOR]

Power performance of lithium-ion batteries (LIBs) is generally controlled by the Li + diffusion within crystalline framework of electrode materials, and thus nano-sized electrode materials with shortened diffusion length have been widely used to build high power LIBs. However, the undesired effects from nano-sized electrode materials, such as low tap density, low thermal stability and increased interface also discount the overall performance of LIBs. Accordingly, it is desired to develop high power LIBs with micro-sized electrode materials. Herein, we demonstrate that hard carbon displays fast Li-storage kinetics which is not controlled by Li + diffusion in the crystalline framework. Furthermore, it is found that micro-sized spinel LiNi 0.5 Mn 1.5 O 4 and LiMn 2 O 4 have high rate performance, owing to their three-dimensional channels for Li + diffusion. Finally, the micro-sized spinel LiNi 0.5 Mn 1.5 O 4 (or Li 1.1 Mn 2 O 4 ) and micro-sized hard carbon are used as cathode and anode, respectively, to fabricate the full cells that exhibit supercapacitor-like high power performance. The achieved results point a way to develop high power LIBs besides nano-sizing electrode materials. [ABSTRACT FROM AUTHOR]

Cobalt-free perovskites, Ln 0.5 Sr 0·5 Fe 0·8 Cu 0·2 O 3−δ (Ln = La, Pr, and Nd), are systematically evaluated as the cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs) using Gd 0.1 Ce 0·9 O 1.95 as the electrolyte. The samples exhibit an orthorhombic perovskite structures, and their cell volumes decrease as the ionic radius of Ln decreases. Both the oxygen vacancy content and the magnitude of lattice oxygen release per formula unit increase in the temperature range from 370 °C to 850 °C as the ionic radius of Ln decreases. Ln 0.5 Sr 0.5 Fe 0.8 Cu 0.2 O 3−δ is chemically and thermally compatible with the Gd 0.1 Ce 0·9 O 1.95 electrolyte. In the temperature range of 600 °C-750 °C, Nd 0.5 Sr 0·5 Fe 0·8 Cu 0·2 O 3−δ possesses the highest catalytic activity for the oxygen reduction reaction with area specific resistance values of 0.071 Ω cm 2 and 0.141 Ω cm 2 at 750 °C and 700 °C, respectively. The maximum power densities of the anode-supported single cells at 800 °C and 700 °C are 1003.7 mW cm −2 and 516.7 mW cm −2 for Pr 0.5 Sr 0·5 Fe 0·8 Cu 0·2 O 3−δ and 944.5 mW cm −2 and 530.2 mW cm −2 for Nd 0.5 Sr 0·5 Fe 0·8 Cu 0·2 O 3−δ , respectively. Ln 0.5 Sr 0.5 Fe 0.8 Cu 0.2 O 3−δ is shown to be a promising cathode material for IT-SOFCs. [ABSTRACT FROM AUTHOR]

An understanding of the relationships between the processing, compositions, and properties of perovskites is vitally important in the search for high performance cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs). In this work, the properties of PrBa 1−x Co 2 O 5+δ (x = 0.00–0.10) double perovskites were modified by introducing K during synthesis, and their performances as the cathode materials for IT-SOFCs were then characterized. The addition of K resulted in a greater cation deficiency in the double perovskites, improving bulk oxygen transport. However, K addition also markedly decreased the Co ion content on the perovskites' surfaces, which significantly deteriorated the perovskites’ electrochemical performances related to the surface exchange of oxygen. [ABSTRACT FROM AUTHOR]

0.5Li 2 MnO 3 ·0.5LiMn 1/3 Ni 1/3 Co 1/3 O 2 microspheres are prepared by a slurry spray-drying process (SD-LLO) with subsequent heat treatment. SEM images show that the SD-LLO microspheres are composed of nano-size primary particles. These particles are quite different from conventional LLO microspheres, which are composed of micron-scale plate-like primary particles prepared by a co-precipitation method (CP-LLO). The SD-LLO material experiences a smaller voltage drop during cycling than CP-LLO when used as cathode material in lithium-ion batteries. High-resolution transmission electron microscopy (HR-TEM) and energy dispersive spectroscopy (EDS) indicate that the smaller voltage drop of SD-LLO can be attributed to a more homogeneous distribution of transition metals. [ABSTRACT FROM AUTHOR]

[Display omitted] • The K, Fe double doping strategy for ZnMn 2 O 4 is proposed for the first time. • Oxygen defects are formed by double doping. • K, Fe-ZMO with lower formation energy has better structural stability. • The modification is beneficial to improve the electrical conductivity. • The rate and cycling stability of K, Fe-ZMO is significantly improved. In aqueous zinc-based batteries (ZBBs), manganese-based materials are considered to be potential cathode materials. However, sluggish electrochemical reaction kinetics and problems with manganese dissolution have limited their further development. Herein, K and Fe double-doped ZnMn 2 O 4 (K, Fe-ZMO) is demonstrated to be effective in solving the above problems. The doping of K and Fe can form oxygen defects to enhance the conductivity of the material and the diffusion of Zn2+. Interestingly, the K, Fe-doped ZnMn 2 O 4 shows a high specific capacity of 221.2 mA h g−1 (0.1 A g−1) after 50 cycles, more than the pure ZnMn 2 O 4 (137.3 mA h g−1). The capacity retention (≈88.1% 500 cycles at 1.0 A g−1) is also better than ZnMn 2 O 4 cathode (≈27.5% 370 cycles at 1.0 A g−1). Density functional theory (DFT) calculations prove that double doping and oxygen defects can facilitate electronic rearrangement to enhance the conductivity, which finally improves the reaction kinetics and electrochemical performance of the K, Fe-ZMO. Furthermore, the modifications can also reduce the formation energy so as to effectively stabilize the Mn-O bond and Fe-O of K, Fe-ZMO, which alleviates the dissolution of manganese. We believe that the strategy proposed in this work will provide another example for the practical application of manganese-based materials in aqueous zinc-based batteries. [ABSTRACT FROM AUTHOR]

Rechargeable aqueous zinc-ion batteries (ZIBs) are possible future replacements for large-scale energy storage devices because of their safety, low cost, and abundance of materials. Finding a competitive cathode material suitable for zinc-ion insertion/de-insertion, needed to achieve high reversible capacity and long cycle stability, is one of the most important and arduous challenges. For the first time, nickel and cobalt co-substituted spinel ZnMn 2 O 4 nanoparticles, homogeneously loaded onto N-doped reduced graphene oxide (ZnNi x Co y Mn 2-x-y O 4 @N-rGO), were synthesised through a one-step hydrothermal method and applied as a cathode material to accommodate the intercalation of zinc ions. The as-prepared ZnNi x Co y Mn 2-x-y O 4 @N-rGO displayed excellent electrochemical performance, with a reversible capacity of 95.4 mA h g−1, achieved at 1000 mA g−1 after 900 cycles, and a capacity retention ratio of 79%. When the current density increased from 10 mA g−1 to 1500 mA g−1, high capacity (200.5 mA h g−1 to 93.5 mA h g−1) was achieved, which was much higher than that of ZMO@N-rGO without nickel and cobalt co-substituting (184 mA h g−1 to 59.2 mA h g−1), demonstrating excellent rate performance. These excellent electrochemical properties are attributed to the co-substituting of nickel and cobalt elements, which is an effective approach to promote Zn2+ de-intercalation and to stabilize the spinel structure in order to suppress the Jahn-Teller distortion of Mn3+. Therefore, nickel and cobalt co-substituting of spinel ZnMn 2 O 4 @N-rGO with a stable structure opens up new possibilities for large-scale application of rechargeable, aqueous ZIBs. Image 1 • Nickel and cobalt co-substituted spinel ZnMn 2 O 4 nanoparticles were synthesised • The ultrafine ZnNi 0.39 Co 0.59 Mn 0.98 O 4 loaded onto N-doped reduced graphene oxide. • The ZnNi 0.39 Co 0.59 Mn 0.98 O 4 @N-rGO exhibited excellent performance as a cathode for SIBs. • Nickel and cobalt co-substituting stabilized the spinel structure. • The N-doped graphene network ensured highly electronic conductivity. [ABSTRACT FROM AUTHOR]