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Li-B alloy can be used as a lithium-metal anode, and this alloy maintains the entire structure of Li7B6 constituents after the removal of free Li. In this study, a compact Li-Al layer which allows electron and ion transport to form in situ on the Li-B electrode was developed to solve the fundamental challenges of the Li-metal anode. Results of symmetric-cell tests show that the Li-Al layer coating on Li-B electrode can improve cyclic life over 1200 h at a current density of 0.2 mA cm−2, whereas bare Li-B electrode has stable cycles not exceeding 800 h. Results of scanning electron microscopy analysis demonstrate that Li deposition occurs beneath the Li-Al layer, and that the Li-Al alloy layer effectively reduces Li-metal corrosion and suppress the formation of Li dendrites. When matched with LiNi0.8Co0.15Al0.05O2 cathode, the Li-B with Li-Al layer shows improved cycle stability and lower voltage difference than bare Li-B anode.

The effects of an Li-Al layer on the modified-Li anode based on solid state batteries are studied. The structure, surface morphology, and cyclic stability of the modified-Li anode are examined by X-ray diffraction spectroscopy, scanning electron microscopy, and electrochemical tests. Results show that interphase layer can prevent Li from reacting with Li1.5Al0.5Ge1.5(PO4)3 and displays a much better cycling stability compared with the bare-Li anode used in symmetric cells. The assembled solid state batteries with modified-Li anode and LiMn0.8Fe0.2PO4 cathode can deliver an initial discharge capacity of 153 mAh g−1 with good cyclic stability and rate performance at 50 °C. The reason for this is that the Li-Al alloy interphase layer can prevent localised Li enrichment, then suppress lithium dendrite growth, and the Li-Al layer on the anode possesses good stability in the presence of Li1.5Al0.5Ge1.5(PO4)3 powder and better interphase contact results between the anode and solid electrolyte in solid state batteries.

The most important aspect in the development of Si-based photovoltaic technologies is the passivation of the Si wafer surface. Here, we show that Poly(3,4-ethylthiophene):polystyrenesulfonate (PEDOT:PSS) thin films, frequently used in organic/inorganic hybrid solar cells as emitter layers, provide an excellent surface passivation with a millisecond (ms) level effective minority carrier lifetime ( τ eff ). More importantly, we find that this passivation effect is dominated by the PSS species in PEDOT:PSS rather than PEDOT ones. The PSS thin film passivation yields a high τ eff of 9.4 ms on a high-resistivity Si wafer. The interface nature of PSS/Si is unveiled by the X-ray photoelectron spectroscopy and first-principles total-energy calculations together. An electrochemical passivation mechanism is clarified: the Si sub-oxides form at PSS/Si interface by the electrochemical grafting O groups in PSS onto Si surface, which can be controlled by injecting holes or electrons into the Si surface, leading to a switchable interface state between oxidation and deoxidation. To examine the application of the passivation strategy in real devices, we develop a polymer-passivated both-sides Si heterojunction solar cell with light-induced enhancement of photovoltaic performances, which is consistent with the light-induced enhancement of τ eff .

In this study, tungsten trioxide (WO3) thin films were prepared at different working pressures by direct current (DC) reactive magnetron sputtering for the application in all thin film electrochromic devices (ATF-ECDs). The target voltage was used to monitor the target status and employed as an advanced technology to choose process parameter set for special working points in particular for reactive magnetron sputtering of transition metal oxides here. Various properties of WO3 thin films including deposition rate, optical property, chemical composition, crystal structure, morphology, electrochemical properties as well as electrochromic property were systematically investigated. In addition, the device performances of the ATF-ECDs including optical modulation, coloration efficiency, switch time and stability were investigated as well. The ATF-ECDs with WO3 thin films sputtered at 4.0 Pa showed a high optical modulation (TT at 600 nm) of up to 70.9% and a relatively fast switch time (2 s for bleaching step and 13 s for coloring step) as well as a better cycle stability.

Flexible and freestanding sulfur electrode is of great importance for the fabrication of high-performance flexible lithium-sulfur batteries. However, electrodes with high sulfur loading usually exhibit unsatisfactory mechanical flexibility and inferior electrochemical stability. Herein, we report a high sulfur loading multilayer electrode with good flexibility, which is constructed using reduced graphene oxide and conductive polymer film by a simple multilayer coating method. The prepared electrode possesses high flexibility and electrochemical performance under sulfur loading of 6.1 mg cm−2 and sulfur content of 60% in the entire electrode. The electrode can even release a reversible capacity of 559 mAh g−1 after 500 cycles at a rate current density of 2 C, corresponding to a capacity decay rate of 0.057% per cycle. The stable electrochemical properties are due to the fact that conductive polymer films and reduced graphene oxide sheets could effectively inhibit the dissolution and diffusion of the polysulfide compounds.