Germanium is a highly promising anode material for lithium-ion batteries as a consequence of its large theoretical specific capacity, good electrical conductivity, and fast lithium ion diffusivity. In this work, Co3O4 nanowire array fabricated on nickel foam was designed as a nanostructured current collector for Ge anode. By limiting the voltage cutoff window in an appropriate range, the obtained Ge anode exhibits excellent lithium storage performance in half- and full-cells, which can be mainly attributed to the designed nanostructured current collector with good conductivity, enough buffering space for the volume change, and shortened ionic transport length. More importantly, the assembled Ge/LiCoO2 full-cell shows a high energy density of 475 Wh/kg and a high power density of 6587 W/kg. A high capacity of 1184 mA h g(-1) for Ge anode was maintained at a current density of 5000 mA g(-1) after 150 cycles.

To satisfy the increasing energy demands of portable electronics, electric vehicles, and miniaturized energy storage devices, improvements to lithium‐ion batteries (LIBs) are required to provide higher energy/power densities and longer cycle lives. Group IVA element (Si, Ge, Sn)‐based alloying/dealloying anodes are promising candidates for use as electrodes in next‐generation LIBs owing to their extremely high gravimetric and volumetric capacities, low working voltages, and natural abundances. However, due to the violent volume changes that occur during lithium‐ion insertion/extraction and the formation of an unstable solid electrolyte interface, the use of Group IVA element‐based anodes in commercial LIBs is still a great challenge. Evaluating the electrochemical performance of an anode in a full‐cell configuration is a key step in investigating the possible application of the active material in LIBs. In this regard, the recent progress and important approaches to overcoming and alleviating the drawbacks of Group IVA element‐based anode materials are reviewed, such as the severe volume variations during cycling and the relatively brittle electrode/electrolyte interface in full‐cell LIBs. Finally, perspectives and future challenges in achieving the practical application of Group IVA element‐based anodes in high‐energy and high‐power‐density LIB systems are proposed.

Self-supporting Co 3 O 4 with lemongrass-like morphology exhibits excellent rate capability and cyclic stability for high-performance Li ion batteries as electrodes. It retains a high reversible capacity of up to 981 mA h g À1 after 100 cycles at a rate of 0.5 C and a capacity higher than 381 mA h g À1 even at a rate as high as 10 C.Recently, Co 3 O 4 has attracted much attention and become one of the most promising anode materials for the next generation of lithium ion batteries (LIBs) due to its superior specific capacity (890 mA h g À1 in theory), low cost, and environmental friendliness. [1][2][3][4][5] Until recently, Co 3 O 4 powders with various morphologies have been synthesized as anode materials, including hollow spheres, 6 nanofibers, 7 nanobelts, 8 nanotubes, 9 nanocapsules, 10 nanocages, 11 and so on. Despite the high capacities in the first few cycles, most of the powder materials display unsatisfactory cycling stability mainly owing to the poor electronic conduction. Several strategies have been proposed to solve the problems, in which self-supporting Co 3 O 4 nanostructures grown directly on current-collecting substrates represent an attractive approach. Li et al. have prepared mesoporous Co 3 O 4 nanowire arrays on Ti foil by a template-free method, which deliver a capacity of 700 mA h g À1 after 20 cycles at a current of 111 mA g À1 . 12 Fan et al. have synthesized freestanding Co 3 O 4 porous nanosheets on nickel foil and found that, when the architecture is used as an anode for LIBs, the capacity maintains 631 mA h g À1 after 50 cycles at a constant current of 150 mA g À1 . 13 Wang et al. have prepared the Co 3 O 4 nanobelt arrays on Ti foil, which retain a specific capacity of 770 mA h g À1 over 25 cycles at a current density of 177 mA g À1 . 14 Li et al. have fabricated Co 3 O 4 nanowire arrays directly on steel coins coated by gold nanoparticles, which show a capacity of 743 mA h g À1 after 50 cycles at a current density of 100 mA g À1 , but the capacities gradually fade at higher discharge rates. 15 It is clear that, as a qualified anode material for LIBs for high-power applications, further

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.201902363. Lithium-sulfur batteries (LSBs) have shown great potential for application in high-density energy storage systems. However, the performance of LSBs is hindered by the shuttle effect and sluggish reaction kinetics of lithium polysulfides (LiPSs). Herein, heterostructual Nb 2 O 5 nanocrystals/ reduced graphene oxide (Nb 2 O 5 /RGO) composites are introduced into LSBs through separator modification for boosting the electrochemical performance. The Nb 2 O 5 /RGO heterostructures are designed as chemical trappers and conversion accelerators of LiPSs. Originating from the strong chemical interactions between Nb 2 O 5 and LiPSs as well as the superior catalytic nature of Nb 2 O 5 , the Nb 2 O 5 /RGO nanocomposite possesses high trapping efficiency and efficient electrocatalytic activity to long-chain LiPSs. The effective regulation of LiPSs conversion enables the LSBs enhanced redox kinetics and suppressed shuttle effect. Moreover, the Nb 2 O 5 /RGO nanocomposite has abundant sulfophilic sites and defective interfaces, which are beneficial for the nucleation and growth of Li 2 S, as evidenced by analysis of the cycled separators. As a result, LSBs with the Nb 2 O 5 /RGOmodified separators exhibit excellent rate capability (816 mAh g −1 at 3 A g −1 ) and cyclic performance (628 mAh g −1 after 500 cycles). Remarkably, high specific capacity and stable cycling performance are demonstrated even at an elevated temperature of 50 °C or with higher sulfur loadings. Lithium-Sulfur Batteries www.advancedsciencenews.com

In this work, a planar light-controlled artificial synapse having high photosensitivity (Ion/Ioff > 1000) with a high photocurrent and a low dark current is realized based on a ZnO thin film grown by radiofrequency sputtering.