Throughout years, the two-step spin-coating process is the most common method to prepare organic lead halide perovskite materials. However, the short reaction time of dropping the solution at the second step means that PbI₂ cannot be completely transformed into perovskite phase. To solve this problem, we report the introduction of glycine hydrochloride (GlyHCl) into the second step of the two-step spin-coating process to prepare a FA_0.9MA_0.1PbI₃-x%-GlyHCl perovskite material (namely FAMA-x%-GlyHCl, where FA = formamidinium, MA = methylammonium, and x% stands for the molar ratio of GlyHCl added in FA iodide/MA iodide (FAI/MAI) precursor solution). The Cl⁻ ion in GlyHCl assists the formation of α-phase perovskite, and the –COO⁻ group coordinates with Pb²⁺ cation in a bridging way, making up for the anion vacancy in perovskite lattice and resulting in high absorption intensity. The perovskite solar cells (PSCs) based on FAMA-9%-GlyHCl achieve a long carrier lifetime (527.0 ns), a photoelectric conversion efficiency (PCE) of 19.40% and good thermal stability, maintaining 85.8% of the initial PCE after being continuously heated at 60 °C for 500 h. This study helps to solve the problem of incomplete reaction in the two-step spin-coating process and puts forward a new solution for preparing high coverage perovskite films with large grain size.

All-inorganic perovskites, adopting cesium (Cs⁺) cation to completely replace the organic component of A-sites of hybrid organic–inorganic halide perovskites, have attracted much attention owing to the excellent thermal stability. However, all-inorganic iodine-based perovskites generally exhibit poor phase stability in ambient conditions. Herein, we propose an efficient strategy to introduce antimony (Sb³⁺) into the crystalline lattices of CsPbI₂Br perovskite, which can effectively regulate the growth of perovskite crystals to obtain a more stable perovskite phase. Due to the much smaller ionic radius and lower electronegativity of trivalent Sb³⁺ than those of Pb²⁺, the Sb³⁺ doping can decrease surface defects and suppress charge recombination, resulting in longer carrier lifetime and negligible hysteresis. As a result, the all-inorganic perovskite solar cells (PSCs) based on 0.25% Sb³⁺ doped CsPbI₂Br light absorber and screen-printable nanocarbon counter electrode achieved a power conversion efficiency of 11.06%, which is 16% higher than that of the control devices without Sb³⁺ doping. Moreover, the Sb³⁺ doped all-inorganic PSCs also exhibited greatly improved endurance against heat and moisture. Due to the use of low-cost and easy-to-process nanocarbon counter electrodes, the manufacturing process of the all-inorganic PSCs is very convenient and highly repeatable, and the manufacturing cost can be greatly reduced. This work offers a promising approach to constructing high-stability all-inorganic PSCs by introducing appropriate lattice doping.

Electrocatalytic carbon dioxide (CO₂) reduction is considered as an economical and environmentally friendly approach to neutralizing and recycling greenhouse gas CO₂. However, the design of preeminent and robust electrocatalysts for CO₂ electroreduction is still challenging. Herein, we report the in-situ growth of dense CuO_x nanowire forest on 3D porous Cu foam (CuO_x-NWF@Cu-F), which can be directly applied as a freestanding and binder-free working electrode for highly effective electrocatalytic CO₂ reduction. By adjusting the surface morphology and chemical composition of CuO_x nanowires via surface reconstruction, large electrochemically active surface area and abundant Cu(+1) sites were generated, leading to remarkable activity for CO₂ electroreduction. The as-prepared hierarchical conductive electrode exhibited an enhanced Faradaic efficiency of 15.0% for ethanol formation (FE_C2H5OH) and a total Faradaic efficiency of 69.4% for all carbonaceous compounds (FE_C-total) at a mild applied potential of –0.45 V vs. RHE in 0.1 M KHCO₃ electrolyte. It achieved a 4-fold increase in FE_C-total than that of Cu nanowire forest supported on 3D porous Cu foam (Cu-NWF@Cu-F) obtained by in-situ reduction of the CuO_x-NWF@Cu-F via annealing at H₂ atmosphere, and thereby effectively suppressed the hydrogen evolution side-reaction.

Lithium-ion capacitor (LIC) has been regarded as a promising energy storage system with high powder density and high energy density. However, the kinetic mismatch between the anode and the cathode is a major issue to be solved. Here we report a high-performance asymmetric LIC based on oxygen-deficient black-TiO_2−x/graphene (B-TiO_2−x/G) aerogel anode and biomass derived microporous carbon cathode. Through a facile one-pot hydrothermal process, graphene nanosheets and oxygen-vacancy-rich porous B-TiO_2−x nanosheets were self-assembled into three-dimensional (3D) interconnected B-TiO_2−x/G aerogel. Owing to the rich active sites, high conductivity and fast kinetics, the B-TiO_2−x/G aerogel exhibits remarkable reversible capacity, high rate capability and long cycle life when used as anode material for lithium ion storage. Moreover, density functional theory (DFT) calculation reveals that the incorporation of graphene nanosheets can reduce the energy barrier of Li⁺ diffusion in B-TiO_2−x. The asymmetric LIC based on B-TiO_2−x/G aerogel anode and naturally-abundant pine-needles derived microporous carbon (MPC) cathode work well within a large voltage window (1.0-4.0 V), and can deliver high energy density (166.4 Wh∙kg⁻¹ at 200 mA∙g⁻¹), and high power density (7.9 kW∙kg⁻¹ at 17.1 Wh∙kg⁻¹). Moreover, the LIC shows a high capacitance retention of 87% after 3, 000 cycles at 2, 000 mA∙g⁻¹. The outstanding electrochemical performances indicate that the rationally-designed LICs have promising prospect to serve as advanced fast-charging energy storage devices.