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The demand for energy storage devices has increased significantly, and the sustainable development of lithium-ion batteries is limited by scarce lithium resources. Therefore, alternative sodium-ion batteries which are rich in resource may become more competitive in the future market. In this work, we synthesized low-cost SnS 2 /C and FeS 2 /C anode materials of sodium-ion batteries which used waste crab shells as biomass carbon precursor. The SnS 2 nanosheet and FeS 2 nanosphere structures are deposited on the crab shell-derived carbon through simple hydrothermal reaction. Due to the coexistence of transition metal dichalcogenides (TMDs) and crab-derived biomass carbon, the anode material has excellent cycle stability and rate performance. SnS 2 /C and FeS 2 /C deliver capacities of 535.4 and 479 mA h g -1 at the current density of 0.1 A g -1 , respectively. This study explored an effective and economical strategy to use biomass and TMDs to construct high-performance sodium-ion batteries., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Transition-metal sulfide SnS 2 has aroused wide concern due to its high capacity and nanosheet structure, making it an attractive choice as the anode material in sodium-ion batteries. However, the large volume expansion and poor conductivity of SnS 2 lead to inferior cycle stability as well as rate performance. In this work, FeS 2 was in situ introduced to synchronously grow with SnS 2 on rGO to prepare a heterojunction bimetallic sulfide nanosheet SnS 2 /FeS 2 /rGO composite. The composition and distinctive structure facilitate the rapid diffusion of Na + and improve the charge transfer at the heterogeneous interface, providing sufficient space for volume expansion and improving anode materials' structural stability. SnS 2 /FeS 2 /rGO bimetallic sulfide electrode boasts a capacity of 768.3 mA h g -1 at the current density of 0.1 A g -1 , and 541.2 mA h g -1 at the current density of 1 A g -1 in sodium-ion batteries, which is superior to that of either single metal sulfide SnS 2 or FeS 2 . TDOS calculation further confirms that the binding of FeS 2 /SnS 2 -Na is more stable than FeS 2 and SnS 2 alone. The superior electrochemical performance of the SnS 2 /FeS 2 /rGO composite material makes it a promising candidate for sodium storage.

Temporally intermittent and spatially dispersed renewable energy sources strongly call for large-scale energy storage devices. Aqueous aluminum-ion batteries show great potential for application due to their safety and low cost. Thus far, however, the ideal full-battery configuration is beyond the scope due to shortcomings with regards to suitable anode and cathode materials. Herein, we report a pioneering aqueous aluminum-ion battery system consisting of a Prussian white cathode, 1 M Al 2 (SO 4 ) 3 aqueous electrolyte, and an organic 9,10-anthraquinone anode. The oxidation capability of the Prussian white cathode during the first charging allows for the fabrication of the full battery without pre-inserting aluminum ions, thus making the rocking-chair-type battery feasible. Importantly, the open-framework structure of the Prussian white and distinct enolization charge storage mechanism of 9,10-anthraquinone ensure fast reaction kinetics. The full battery exhibits cycling stability with a capacity retention of 89.1% over 100 cycles at 500 mA g -1 , finishing a cycle in about 10 min. This work provides a pathway for developing rechargeable aqueous aluminum-ion batteries.

Lead halide perovskite has in recent years gained widespread interest due to its excellent physical and chemical properties, as well as superior optoelectronic performance. However, some restrictions still preclude full industrialization of the material, in particular toxicity issues and instability as a result to sensitivity to humidity. Lead-free all-inorganic double perovskite materials have thus recently become a focus of research. Herein, a new narrow bandgap lead-free double perovskite solar cell with a high-quality Cs 2 PtI 6 film is proposed. It exhibits an optical bandgap of 1.37 eV, absorption within a wide range of wavelengths, and a high absorption coefficient. Following optimization, the device displays a best power conversion efficiency of 0.72% with an open-circuit voltage of 0.73 V, a short-circuit current of 1.2 mA/cm 2 , and a fill factor of 0.82. Crucially, it also demonstrates excellent stability when exposed to extreme conditions such as high humidity, high temperature, and UV-light irradiation. Stability tests show that the PSCs can retain almost 80% of the original efficiency over 60 days stored in ambient temperature without any encapsulation, boosting prospects for applications of lead-free perovskite solar cells.

Research on tin-lead (SnPb) perovskite solar cells (PSCs) has gained popularity in recent years because of their low band gap, which could be applied to tandem solar cells. However, most of the work is based on inverted PSCs using PEDOT:PSS as the hole-transport layer as normal-structure PSCs show lower efficiency. In this work, the reason behind the low efficiency of normal-structure SnPb PSCs is elucidated and surface passivation has been tested as a method to overcome the problem. In the case of normal PSCs, at the interface between the titania layer and SnPb perovskite, there are many carrier traps observed originating from Ti-O-Sn bonds. In order to avoid the direct contact between titania and the SnPb perovskite layer, the titania surface is passivated with carboxylic acid C 60 resulting in an efficiency increase from 5.14 to 7.91%. This will provide a direction of enhancing the efficiency of the normal-structure SnPb PSCs through heterojunction engineering.

All-inorganic lead halide perovskite solar cells (PSCs) have drawn widespread interest because of its excellent thermal stability compared to its organic-inorganic hybrid counterpart. Poor phase stability caused by moisture, however, has thus far limited their commercial application. Herein, by modifying the interface between the hole-transport layer (HTL) and the perovskite light absorption layer, and by optimizing the HTL for better energy alignment, we controlled the growth of perovskite, reduced carrier recombination, facilitated carrier injection and transport, and improved the PSC's power conversion efficiency (PCE) and moisture stability. When testing using a positive bias scan, we obtained a significant improvement in PCE, 9.49%, which is the champion efficiency of CsPbIBr 2 -based inverted PSC at present. The stability measurement shows that the passivated CsPbIBr 2 -based inverted PSCs can retain 86% of its initial efficiency after 1000 h preserved in ambient air with 65% relative humidity. This study paves a new way for enhancing the moisture stability and power conversion efficiency of CsPbIBr 2 -based PSCs.

In mixed halide perovskite, the halide phase segregation is commonly observed due to halide ion migration, which causes severe stability issues in perovskite devices. Here, we directly revealed the iodide-migration process via potentiostatic treatment in CsPbIBr 2 perovskite. The absence of iodide ions was reduced significantly via a Sb 2 S 3 interfacial modification. We further employed the density functional theory (DFT) calculation to optimize the geometry positions at the perovskite interface and radial distribution functions (RDF) to analyze the atom perturbation. The simulation yielded a slight distortion of the perovskite lattice at the Sb 2 S 3 -CsPbIBr 2 interface and iodide ion fluctuation was reduced due to the decrease of halide vacancies. In addition, the thermally stimulated current was calculated to evaluate the defect density in the modified perovskite device. Due to the Sb 2 S 3 interaction with perovskite, the device became stable against humidity and maintained its photoactivity over 400 h. The champion efficiency of 9.31% with 26.31% improvement was obtained in modified CsPbIBr 2 perovskite solar cells.

All-inorganic perovskites are attracting increasing attention due to their superior thermal stability than that of the traditional CH 3 NH 3 PbI 3 , while their inferior phase stability in ambient conditions is still an unsolved issue. Here, for the first time, we report the incorporation of niobium (Nb 5+ ) ions into the CsPbI 2 Br perovskite. Results indicate that Nb 5+ can effectively stabilize the photoactive α-CsPbI 2 Br phase by the possible substitution of Pb 2+ . With 0.5% Nb doping, the carbon electrode-based all-inorganic perovskite solar cells achieved a high photoconversion efficiency value of 10.42%, 15% higher than that of the control device. The Nb 5+ incorporation reduces the charge recombination in the perovskite, leading to a champion V oc value of 1.27 V and a negligible hysteresis effect. This work explicates the high compatibility of all-inorganic perovskite materials and unlocks the opportunities for the use of high-valence ions for perovskite property modification.

TiO 2 is commonly used as an electron-transporting material in perovskite photovoltaic devices due to its advantages, including suitable band gap, good photoelectrochemical stability, and simple preparation process. However, there are many oxygen vacancies or defects on the surface of TiO 2 and thus this affects the stability of TiO 2 -based perovskite solar cells under UV light. In this work, a thin (monolayer) SbI 3 modification layer is introduced on the mesoporous TiO 2 surface and the effect at the interface between of TiO 2 and perovskite is monitored by using a quartz crystal microbalance system. We demonstrate that the SbI 3 -modified TiO 2 electrodes exhibit superior electronic properties by reducing electronic trap states, enabling faster electron transport. This approach results in higher performances compared with electrodes without the SbI 3 passivation layer. CH 3 NH 3 PbI 3 perovskite solar cells with a maximum power conversion efficiency of 17.33% in air, accompanied by a reduction in hysteresis and enhancement of the device stability, are reported.

Despite the high efficiency of MAPbI 3 perovskite solar cells, the long term stability and degradation in humid atmosphere are issues that still needed to be addressed. In this work, magnesium iodide (MgI 2 ) was first successfully used as a dopant into MAPbI 3 perovskite prepared in humid air atmosphere. Mg doping decreased the valence band level, which was determined from photoelectron yield spectroscopy. Compared to the pristine MAPbI 3 perovskite film, the 1.0% Mg-doped perovskite film showed increased crystal grain size and formation of pinhole-free perovskite film. Performance of the solar cell was increased from 14.2% of the doping-free solar cell to 17.8% of 1.0% Mg-doped device. Moreover, 90% of the original power conversion efficiency was still retained after storage in 30-40% relative humidity for 600 h.

High-efficiency perovskite solar cells (PSCs) need to be fabricated in the nitrogen-filled glovebox by the atmosphere-controlled crystallization process. However, the use of the glovebox process is of great concern for mass level production of PSCs. In this work, notable efficient CH 3 NH 3 PbI 3 solar cells can be obtained in high humidity ambient atmosphere (60-70% relative humidity) by using acetate as the antisolvent, in which dependence of methyl, ethyl, propyl, and butyl acetate on the crystal growth mechanism is discussed. It is explored that acetate screens the sensitive perovskite intermediate phases from water molecules during perovskite film formation and annealing. It is revealed that relatively high vapor pressure and high water solubility of methyl acetate (MA) leads to the formation of highly dense and pinhole free perovskite films guiding to the best power conversion efficiency (PCE) of 16.3% with a reduced hysteresis. The devices prepared using MA showed remarkable shelf life stability of more than 80% for 360 h in ambient air condition, when compared to the devices fabricated using other antisolvents with low vapor pressure and low water solubility. Moreover, the PCE was still kept at 15.6% even though 2 vol % deionized water was added in the MA for preparing the perovskite layer.

In this study, we demonstrate a simple strategy for obtaining pinhole-free, homogeneous, well-crystallized perovskite films under ambient conditions. The preparation of perovskite film with high light-harvesting efficiency and long carrier lifetime is verified. By applying this film in TiO 2 -based perovskite solar cells (PVSCs), we achieved a high power-conversion efficiency (PCE) of 13.07%, which is doubled with respect to that of the PVSC not subjected to the same improvement procedure (6.54%). High open-circuit photovoltage, photocurrent density, and fill factor are the main contributions to the high PCE that results from low trap density and high recombination resistance of the resultant perovskite films. This work paves a new means for fabricating high-performance perovskite films and PVSC devices in an ambient atmosphere.

The compact layer plays an important role in conducting electrons and blocking holes in perovskite solar cells (PSCs). Here, we use a two-dimensional titania nanosheet (TNS) thin film as the compact layer in CH3NH3PbI3 PSCs. TNS thin films with thicknesses ranging from 8 to 75 nm were prepared by an electrophoretic deposition method from a dilute TNS/tetrabutylammonium hydroxide solution. The TNS thin films contact the fluorine-doped tin oxide grains perfectly. Our results show that a 8-nm-thick TNS film is sufficient for acting as the compact layer. Currently, the PSC with a TNS compact layer has a high efficiency of 10.7% and relatively low hysteresis behavior.

The electron-selective layer (ESL) is an indispensable component of perovskite solar cells (PSCs) and is responsible for the collection of photogenerated electrons. Preparing ESL at a low temperature is significant for future fabrication of flexible PSCs. In this work, solution-processed amorphous WO(x) thin film was prepared facilely at low temperature and used as ESL in PSCs. Results indicated that a large quantity of nanocaves were observed in the WO(x) thin film. In comparison with the conventional TiO2 ESL, the WO(x) ESL exhibited comparable light transmittance but higher electrical conductivity. Compared with the TiO2-based PSCs, PSCs that use WO(x) ESL exhibited comparable photoelectric conversion efficiency, larger short-circuit current density, but lower open-circuit voltage. Electrochemical characterization indicated that the unsatisfied open-circuit voltage and fill factor were caused by the inherent charge recombination. This study demonstrated that this material is an excellent candidate for ESL.

Low cost, high efficiency, and stability are straightforward research challenges in the development of organic-inorganic perovskite solar cells. Organolead halide is unstable at high temperatures or in some solvents. The direct preparation of a carbon layer on top becomes difficult. In this study, we successfully prepared full solution-processed low-cost TiO2/CH3NH3PbI3 heterojunction (HJ) solar cells based on a low-temperature carbon electrode. Power conversion efficiency of mesoporous (M-)TiO2/CH3NH3PbI3/C HJ solar cells based on a low-temperature-processed carbon electrode achieved 9%. The devices of M-TiO2/CH3NH3PbI3/C HJ solar cells without encapsulation exhibited advantageous stability (over 2000 h) in air in the dark. The ability to process low-cost carbon electrodes at low temperature on top of the CH3NH3PbI3 layer without destroying its structure reduces the cost and simplifies the fabrication process of perovskite HJ solar cells. This ability also provides higher flexibility to choose and optimize the device, as well as investigate the underlying active layers.

We report photovoltaic performances of all-solid state Sn/Pb halide-based perovskite solar cells. The cell has the following composition: F-doped SnO2 layered glass/compact titania layer/porous titania layer/CH3NH3SnxPb(1-x)I3/regioregular poly(3-hexylthiophene-2,5-diyl). Sn halide perovskite itself did not show photovoltaic properties. Photovoltaic properties were observed when PbI2 was added in SnI2. The best performance was obtained by using CH3NH3Sn0.5Pb0.5I3 perovskite. 4.18% efficiency with open circuit voltage 0.42 V, fill factor 0.50, and short circuit current 20.04 mA/cm(2) are reported. The edge of the incident photon to current efficiency curve reached 1060 nm, which was 260 nm red-shifted compared with that of CH3NH3PbI3 perovskite solar cells.

Three classes (carbides, nitrides and oxides) of nanoscaled early-transition-metal catalysts have been proposed to replace the expensive Pt catalyst as counter electrodes (CEs) in dye-sensitized solar cells (DSCs). Of these catalysts, Cr(3)C(2), CrN, VC(N), VN, TiC, TiC(N), TiN, and V(2)O(3) all showed excellent catalytic activity for the reduction of I(3)(-) to I(-) in the electrolyte. Further, VC embedded in mesoporous carbon (VC-MC) was prepared through in situ synthesis. The I(3)(-)/I(-) DSC based on the VC-MC CE reached a high power conversion efficiency (PCE) of 7.63%, comparable to the photovoltaic performance of the DSC using a Pt CE (7.50%). In addition, the carbide catalysts demonstrated catalytic activity higher than that of Pt for the regeneration of a new organic redox couple of T(2)/T(-). The T(2)/T(-) DSCs using TiC and VC-MC CEs showed PCEs of 4.96 and 5.15%, much higher than that of the DSC using a Pt CE (3.66%). This work expands the list of potential CE catalysts, which can help reduce the cost of DSCs and thereby encourage their fundamental research and commercial application.

A highly efficient dye-sensitized solar cell (DSC) was fabricated using a nanocrystalline nitrogen-doped titania electrode. The properties of the nitrogen-doped titania powder, film, and solar cell were investigated. The substitution of oxygen sites with nitrogen atoms in the titania structure was confirmed by X-ray photoemission spectroscopy (XPS). The UV-vis spectrum of the nitrogen-doped powder and film showed a visible light absorption in the wavelength range from 400 to 535 nm. An enhancement of the incident photon-to-current conversion efficiency (IPCE) in the range of 380-520 nm and 550-750 nm was observed. An 8% overall conversion efficiency has been achieved. The results of the stability test indicated that the solar cell fabricated by the nitrogen-doped titania exhibited great stability.