Uncontrolled growth of lithium dendrites during cycling has remained a challenging issue for lithium metal batteries. Thus far, various approaches have been proposed to delay or suppress dendrite growth, yet little attention has been paid to the solutions that can make batteries keep working when lithium dendrites are already extensively present. Here we develop an industry-adoptable technology to laterally direct the growth of lithium dendrites, where all dendrites are retained inside the compartmented copper current collector in a given limited cycling capacity. This featured electrode layout renders superior cycling stability (e.g., smoothly running for over 150 cycles at 0.5 mA cm−2). Numerical simulations indicate that reduced dendritic stress and damage to the separator are achieved when the battery is abusively running over the ceiling capacity to generate protrusions. This study may contribute to a deeper comprehension of metal dendrites and provide a significant step towards ultimate safe batteries.

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The storage process of Zn 2+ ion into α-MnO 2 has been investigated by electrochemical impedance spectrum. A new phase formation process has been recognized. The equivalent circuit model and the impedance expression have been built up to characterize the storage of Zn 2+ ion into α-MnO 2 . It is found that the storage process of Zn 2+ ions is mainly determined by the phase change. With the decrease of potential, Zn 2+ ions begin to insert into MnO 2 and phase change occurs, which leads to a significant increase on phase change resistance (R T ). We also investigated the relationship between the phase change and the phase angle. It is mathematically calculated that maximum phase angle (| | 0 ) at low frequency domain shows a logarithmic dependence on R T , which is confirmed by the experimental results. By using | | 0 directly from Bode plot, we can easily monitor the phase change and the storage process of zinc ion into MnO 2 .Due to the energy crisis and environmental deterioration, our society seeks renewable energy sources for a sustainable growth of human population and living standards. Solar, wind, water, nuclear, tidal, geothermal energies are now considered as the renewable sources to solve the challenges facing society today. Along with energy production, renewable energy systems need the ability to store energy for reuse on various purposes. The use of electricity generated from these renewable sources requires efficient distributed electrical energy storage by batteries on scales ranging from public utilities to miniaturized portable electronic devices. Batteries, which are playing a key role on the utilization of the renewable energy sources, normally store energy through an electrochemical way. 1 There are several kinds of rechargeable batteries, for example, lithium ion, nickel metal hybrid, nickel cadmium, lead acid batteries, serving as the efficient devices for the energy storage. 2-7 Lithium ion battery is now a rising star to meet the demand of high energy density. The battery chemistry of a lithium ion battery utilizes the migration of lithium ion (Li + ion) between a cathodic lithium metal oxide (for example LiCoO 2 ) and an anodic carbon (for example graphite). 2 Lithium ion running between cathode and anode is nothing but a medium for the electric storage. Despite the high energy density demand, our society also requires the safety, environmentally friendly, and low cost battery to meet the demand of the next generation electric or electrical devices. 8 More recently, the so-called energetic zinc ion chemistry has been proposed by us and a battery named as zinc ion battery has been built up. 9,10 In such a battery, the battery chemistry is based on the migration of Zn 2+ ions between α-MnO 2 cathode and Zn anode within a mild aqueous ZnSO 4 electrolyte. This battery shows a great potential on the applications where both power and energy needs.In our previous works, we found that alpha manganese dioxide (α-MnO 2 ) can store and release zinc ion (Zn 2+ ) fast and reversibly. The storage/relea...

Conventional acidic water electrolysis for large-scale hydrogen production needs to involve noble metal catalyst for anode to resist electrochemical oxidation; while alkaline electrolysis can provide better anode protection, but hydrogen...

Fractal metallic dendrites have been drawing more attentions recently, yet they have rarely been explored in electronic printing or packaging applications because of the great challenges in large-scale synthesis and limited understanding in such applications. Here we demonstrate a controllable synthesis of fractal Ag micro-dendrites at the hundred-gram scale. When used as the fillers for isotropically electrically conductive composites (ECCs), the unique three-dimensional fractal geometrical configuration and low-temperature sintering characteristic render the Ag micro dendrites with an ultra-low electrical percolation threshold of 0.97 vol% (8 wt%). The ultra-low percolation threshold and self-limited fusing ability may address some critical challenges in current interconnect technology for microelectronics. For example, only half of the laser-scribe energy is needed to pattern fine circuit lines printed using the present ECCs, showing great potential for wiring ultrathin circuits for high performance flexible electronics.

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Lithium (Li) metal can deliver the highest theoretical specific capacity among all lithium battery anodes, yet its application is significantly hindered due to a series of critical challenges (poor cycleability and safety risks, etc.), most of which are related to uncontrolled Li dendrite growth. However, the dendrite problem cannot be fully avoided because of a number of complicated multi-physical field factors, especially under high cycling rate and high capacity conditions. An ideal situation is when the battery can automatically restore the uncontrolled dendrites growth itself, whenever it appears during the entire cycling lifespan; however, discussion on this issue is rare. A periodically conductive/dielectric lamella scaffold is developed for hosting Li metal to realize a "self-correction" functionality, which can automatically synchronize Li deposition/stripping by periodically re-homogenizing electric field distribution around irregular Li protrusions. Consequently, dendrite-free Li plating/stripping with high Coulombic efficiency can be achieved even at 5 mA cm −2 and an ultrahigh cycling capacity of 15 mAh cm −2 . Notably, a maximal cumulative plating capacity of 4000 mAh cm −2 with Li utilization of 50% is realized, outperforming most recently reported results. This work provides new insights for designing future smart high-performance metal anode batteries for real application.commercialization. For decades, numerous efforts have been devoted to eliminating/ delaying Li dendrites, involving interface engineering, [4][5][6] electrolyte modification, [7][8][9] and adopting 3D lithophilic host, [10,11] etc. However, the tendency for Li-dendrite formation cannot be fully avoided during repeated Li plating/stripping process, as it is thermodynamically and kinetically favorable. [12,13] Owing to the intrinsically intricate influencing factors (e.g., Li ion concentration, local potentials, local current, temperature distributions, [14][15][16][17] and interface energy difference. [18] ), unsynchronized and irregular Li metal propagation is prone to occur in electrochemical "hotspots" during Li plating, which could trigger self-amplified parasitic and dendritic growth (Figure 1a). Although intensive fundamental studies with well-established models have explored the growth mechanism of Li dendrites, technically it is extremely difficult to predict their emergence and manage their growth, especially when batteries are cycling under high a current density and high capacity conditions. To solve the safety problem of Li metal anodes and extend their cycle life, a few strategies have been proposed, including modulating the dendrite growth directions, [12,19,20] reacting dendrites with a modified separator, [21] healing dendrites by heating, [22] and equipping battery with real-time monitoring systems,. [23,24] In particular, compositing Li metal with 3D hosts has been demonstrated as a promising solution to stabilize Li metal plating at high working current density and high capacity. [25] Specifically, employing an...

Poly(ethylene oxide) (PEO) nanofibers were prepared by electrospinning PEO solution with a mixed solvent of ethanol and deionized water. The results show that the mixed solvent system has noteworthy influences on structures and properties of electrospun PEO nanofibers, including molecular chain orientation, crystallinity degree, surface morphology, fiber diameter, diameter distribution, spinnability, and productivity. With increasing ethanol content in the mixed solvent, wrinkly morphologies appear on the surface of PEO nanofibers due to a high evaporation rate of ethanol during electrospinning process. The dielectric constant, dipole moment, conductivity, density, boiling point, and solubility parameter of the mixed solvent become lower with the ethanol content increasing. Besides, the hydrogen-bonding interactions between PEO and solvents become weaker. As a result, PEO nanofibers with larger diameters, lower molecular chain orientation, and crystallinity degree are obtained.