Dendrite‐Free Flexible Fiber‐Shaped Zn Battery with Long Cycle Life in Water and Air

Fiber‐shaped aqueous rechargeable Zn batteries (FARZBs) show flexibility, good reliability, cost‐effectiveness, high energy/power densities, and high safety that have attracted increasing attention as promising energy storage devices for future wearable applications. However, the development of FARZB is limited by its poor cycling life and inferior charge–discharge performance, mainly suffering from zinc dendrite growth and increasing electrode irreversibility. In this work, dendrite‐free fiber‐shaped Zn//Co₃O₄ rechargeable batteries with a long cycle life tested in water and air, are obtained via tuning the surface binding energy of Zn on the anode using the zincophilic N,O‐functional carbon fiber, as well as engineering the Co₃O₄ cathode with a nanowire array structure. The fiber‐shaped Zn//Co₃O₄ full battery demonstrates remarkable long cycle life in water and air with high energy density, impressive flexibility, and excellent waterproof ability (fully immersed and charged/discharged under water for more than 33 h for 3000 cycles with capacity retention of ≈80%). The reversible electrochemical mechanisms of the FARZBs, without obvious zinc dendrite deposits and structural change of Co₃O₄ nanowires, are confirmed by a series of characterizations. These results demonstrate that the FARZBs are promising power sources for emerging wearable electronics.     

Metal‐Air Batteries: Metal–Air Batteries with High Energy Density: Li–Air versus Zn–Air (Adv. Energy Mater. 1/2011)

In the past decade, there have been exciting developments in the field of lithium ion batteries as energy storage devices, resulting in the application of lithium ion batteries in areas ranging from small portable electric devices to large power systems such as hybrid electric vehicles. However, the maximum energy density of current lithium ion batteries having topatactic chemistry is not sufficient to meet the demands of new markets in such areas as electric vehicles. Therefore, new electrochemical systems with higher energy densities are being sought, and metal‐air batteries with conversion chemistry are considered a promising candidate. More recently, promising electrochemical performance has driven much research interest in Li‐air and Zn‐air batteries. This review provides an overview of the fundamentals and recent progress in the area of Li‐air and Zn‐air batteries, with the aim of providing a better understanding of the new electrochemical systems.     

A Novel Dendrite‐Free Mn2+/Zn2+ Hybrid Battery with 2.3 V Voltage Window and 11000‐Cycle Lifespan

With the increasing energy crisis and environmental pollution, rechargeable aqueous Zn‐based batteries (AZBs) are receiving unprecedented attention due to their list of merits, such as low cost, high safety, and nontoxicity. However, the limited voltage window, Zn dendrites, and relatively low specific capacity are still great challenges. In this work, a new reaction mechanism of reversible Mn²⁺ ion oxidation deposition is introduced to AZBs. The assembled Mn²⁺/Zn²⁺ hybrid battery (Mn²⁺/Zn²⁺ HB) based on a hybrid storage mechanism including Mn²⁺ ion deposition, Zn²⁺ ion insertion, and conversion reaction of MnO₂ can achieve an ultrawide voltage window (0–2.3 V) and high capacity (0.96 mAh cm^?2). Furthermore, the carbon nanotubes coated Zn anode is proved to effectively inhibit Zn dendrites and control side reaction, hence exhibiting an ultrastable cycling (33 times longer than bare Zn foil) without obvious polarization. Benefiting from the optimal Zn anode and highly reversible Mn²⁺/Zn²⁺ hybrid storage mechanism, the Mn²⁺/Zn²⁺ HB shows an excellent cycling performance over 11 000 cycles with a 100% capacity retention. To the best of the authors' knowledge, it is the highest reported cycling performance and wide voltage window for AZBs with mild electrolyte, which may inspire a great insight into designing high‐performance aqueous batteries.     

Metal–Air Batteries with High Energy Density: Li–Air versus Zn–Air

In the past decade, there have been exciting developments in the field of lithium ion batteries as energy storage devices, resulting in the application of lithium ion batteries in areas ranging from small portable electric devices to large power systems such as hybrid electric vehicles. However, the maximum energy density of current lithium ion batteries having topatactic chemistry is not sufficient to meet the demands of new markets in such areas as electric vehicles. Therefore, new electrochemical systems with higher energy densities are being sought, and metal‐air batteries with conversion chemistry are considered a promising candidate. More recently, promising electrochemical performance has driven much research interest in Li‐air and Zn‐air batteries. This review provides an overview of the fundamentals and recent progress in the area of Li‐air and Zn‐air batteries, with the aim of providing a better understanding of the new electrochemical systems.     

Solid Oxide Fuel Cells: Microstructure of Nanoscaled La0.6Sr0.4CoO3‐δ Cathodes for Intermediate‐Temperature Solid Oxide Fuel Cells (Adv. Energy Mater. 2/2011)

Nanocrystalline La_1‐xSr_xCoO_3‐δ (LSC) thin films with a nominal Sr‐content of x = 0.4 were deposited on Ce_0.9Gd_0.1O_1.95 electrolyte substrates using a low temperature sol‐gel process. The structural and chemical properties of the LSC thin films were studied after thermal treatment, which included a calcination step and a variable, extended annealing time at 700 °C or 800 °C. Transmission electron microscopy combined with selected‐area electron diffraction, energy‐dispersive X‐ray spectrometry, and scanning transmission electron microscopy tomography was applied for the investigation of grain size, porosity, microstructure, and analysis of the local chemical composition and element distribution on the nanoscale. The area specific resistance (ASR) values of the thin film LSC cathodes, which include the lowest ASR value reported so far (ASR_chem = 0.023 Ωcm² at 600 °C) can be interpreted on the basis of the structural and chemical characterization.