The electrochemical performance of lithium-ion batteries (LIBs) is closely associated with the solid electrolyte interface (SEI) film formed on the surface of the anode. The pursuit of a stable and dense SEI film to enhance the electrochemical performance of LIBs has been a focal point in this field. In this paper, the additive of lithium difluoro(oxalate)borate (LiODFB) is used into the electrolyte to optimize the SEI film for Li || graphite half-cell and LiFePO4 (LFP) || graphite full-cell. A systematic investigation is conducted to explore the influence patterns and action mechanisms of different LiODFB contents on the electrochemical performance of LIBs. For the first time, it is confirmed through cryo-TEM that LiODFB contributes to the formation of a dense, continuous, and uniform SEI layer, especially rich of LiF. This unique SEI film contributes to the high electrochemical performance of LIBs. The half-cell containing 4 wt.% LiODFB maintains a capacity retention rate of up to 94% after 300 cycles, and the full-cell still exhibits a specific capacity of 102 mAh g−1 after 600 cycles. In contrast, the sample without LiODFB only retains 76% of its capacity after 300 cycles, and 39% after 600 cycles, respectively. Furthermore, the cells with 4 wt.% LiODFB exhibit the lowest charge transfer resistance and oxidation-reduction potential polarization, and highest Li+ transport rates during charge and discharge processes.

Lithium, is the most ideal anode material for lithium-based batteries. However, the overgrowth of lithium dendrites and the low lithium-ion diffusion rate at low temperatures limit the further application of lithium metal anodes. Here, the applied magnetic field is introduced inside the lithium metal anode by using a novel magnetic metal-organic framework as a current collector. The magnetic field can improve the conductivity of this novel current collector, thus accelerating the diffusion of lithium ions in the battery, an advantage that is particularly prominent at low temperatures. In addition, the current collector can stabilize the solid electrolyte interface and inhibit the growth of lithium dendrites, resulting in excellent electrochemical performance. The symmetrical cell at room temperature can exceed 4600 h with a hysteresis voltage of only 9 mV. After 300 cycles at room temperature, the capacity of full cell is still 142 mA h g-1 , and it remains stable for 380 cycles at 5 °C (capacity above 120 mA h g-1 ). The strategy of constructing novel current collector with magnetic field can promote the further application of lithium batteries in extreme conditions such as low temperatures.

Aqueous ammonium ion hybrid supercapacitor (A-HSC) is an efficient energy storage device based on nonmetallic ion carriers (NH4+), which combines advantages such as low cost, safety, and sustainability. However, unstable electrode structures are prone to structural collapse in aqueous electrolytes, leading to fast capacitance decay, especially in host materials represented by vanadium-based oxidation. Here, the Co2+ preintercalation strategy is used to stabilize the VO2 tunnel structure and improve the electrochemical stability of the fast NH4+ storage process. In addition, the understanding of the NH4+ storage mechanism has been deepened through ex situ structural characterization and electrochemical analysis. The results indicate that Co2+ preintercalation effectively enhances the conductivity and structural stability of VO2, and inhibits the dissolution of V in aqueous electrolytes. In addition, the charge storage mechanisms of NH4+ intercalation/deintercalation and the reversible formation/fracture of hydrogen bonds were revealed.

Aqueous ammonium ion hybrid supercapacitor (A‐HSC) combines the charge storage mechanisms of surface adsorption and bulk intercalation, making it a low‐cost, safe, and sustainable energy storage candidate. However, its development is hindered by the low capacity and unclear charge storage fundamentals. Here, the strategy of phosphate ion‐assisted surface functionalization is used to increase the ammonium ion storage capacity of an α‐MoO 3 electrode. Moreover, the understanding of charge storage mechanisms via structural characterization, electrochemical analysis, and theoretical calculation is advanced. It is shown that NH 4 + intercalation into layered α‐MoO 3 is not dominant in the A‐HSC system; rather, the charge storage mainly depends on the adsorption energy of surface “O” to NH 4 + . It is further revealed that the hydrogen bond chemistry of the coordination between “O” of surface phosphate ion and NH 4 + is the reason for the capacity increase of MoO 3 . This study not only advances the basic understanding of rechargeable aqueous A‐HSC but also demonstrates the promising future of surface engineering strategies for energy storage devices.

The transparent Mg:NiO/SnO2 pn junction with potential regulation of Mg-doping has been fabricated via a co-sputtering method. The transparent Mg-doped NiO/SnO2 pn junction (2Mg:NiO/SnO2) exhibits highly transmittance of ~ 85%, photovoltaic conversion enhancement of ~ 3.5 × 103 folds than intrinsic NiO/SnO2 pn junction, and decent stability during 10 week’s continuous cycle. It can be ascribed to the Mg-doping with potential regulation, carrier increasing and band gap extension, can optimize the photo-generated carrier concentration-mobility kinetic equilibrium efficiently to achieve a higher transparent photovoltaic conversion. Additionally, the high-quality pn junction can provide checkless interface for carrier transferring to increase photovoltaic conversion efficiency.

CuI hole transporter-based perovskite solar cells (PSCs) are prepared via a low-temperature in situ deposition method. As demonstrated, the results of x-ray diffraction indicate that the CuI hole-transporter has been fabricated successfully and obtained a better stability, and this can be supported by corresponding scanning electron microscopy, including the dense surface and clear cross section. Furthermore, a maximum incident photon-to-electron conversion efficiency (IPCE) of ∼16.78% is obtained at the CuI-based PSC cell with 2nd time deposition, which can be mainly attributed to the fact that, with the fewer defects in the high-quality interface and matched potential structure for promoting carrier interface immigration/diffusion, the CuI-based hole-transporter exhibits decent hole-extraction to make photo-generated electron/holes have a matched mobility. The remaining PbI 2 , with a better passivation, can inhibit carrier recombination, and both can improve the IPCE efficiently. Therefore, this lower cost and easily controlled technique is suitable for large-scale solar cells.

The development of novel electrochemical energy storage devices is a grand challenge. Here, an aqueous ammonium-ion hybrid supercapacitor (A-HSC), consisting of a layered δ-MnO2 based cathode, an activated carbon cloth anode, and an aqueous (NH4 )2 SO4 electrolyte is developed. The aqueous A-HSC demonstrates an ultrahigh areal capacitance of 1550 mF cm-2 with a wide voltage window of 2.0 V. An amenable peak areal energy density (861.2 μWh cm-2 ) and a decent capacitance retention (72.2% after 5000 cycles) are also achieved, surpassing traditional metal-ion hybrid supercapacitors. Ex situ characterizations reveal that NH4 + intercalation/deintercalation in the layered δ-MnO2 is accompanied by hydrogen bond formation/breaking. This work proposes a new paradigm for electrochemical energy storage.