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Lead iodide (PbI 2) as a defect passivation in perovskite thin films can reduce halide vacancies and improve the performance of perovskite solar cells. However, excess PbI 2 can hurt the device's performance. In the case of perovskite films prepared by two-step sequential deposition, excess PbI 2 is distributed on the surface of perovskite film. The photo-decomposition of PbI 2 and the formation of surface energy barriers can hinder charge transfer in the device, leading to reduced device performance and accelerated device degradation. Inspired by the use of surfactants to control the morphology of perovskite nanocrystals, a dual-functional surfactant (oleamide) was introduced to control the distribution of excess PbI 2 on perovskite films. By adding oleamide, the aggregation distribution of PbI 2 was successfully achieved at the perovskite grain boundaries (GBs), forming a Type-I band alignment and reducing the trap density, thereby prolonging the carrier lifetime. The results show that the power conversion efficiency (PCE) of the device increased from 21.23% to 23.12% after the introduction of oleamide. Compared with the control and oleamide-modified devices, the deep-level defects were reduced by about five orders of magnitude due to the Lewis-base nature of amide groups in oleamide. In addition, due to the aggregation distribution of excess PbI 2 at GBs and the hydrophobicity of oleamide, the modified device showed better stability, maintaining 83% of its initial performance after 1000 h in air. [ABSTRACT FROM AUTHOR]

For studying the mechanism related to the microscopic internal structure of porous carbon additives in lead-carbon batteries, we conducted the electrochemical experiments with a three-electrode system on a lead-doped mesopore-dominated porous carbon (Pb@MC) composite in a Pb 2+ containing H 2 SO 4 electrolyte. Through the electrochemical measures, lead particles on the external surface of carbon could be not only electrodeposited into the nano-sized pores of carbon, but also attached on the pore wall with atomic state, which was observed for the first time by using High Resolution Transmission Electron Microscopy (HRTEM) and Aberration Corrected Scanning Transmission Electron Microscopy (ABF-STEM) with the help of ultrathin sectioning. The nano-lead electrodeposits on the internal surface of carbon didn’t grow up because they were confined by the nano-sized pores of carbon. These nano-lead deposits could not only effectively inhibit the hydrogen evolution, but also contribute the pseudocapacitance and enhance the reversible reaction of Pb/PbSO 4 , and thus result in the longer cycle performance of lead-carbon batteries. [ABSTRACT FROM AUTHOR]

Ni-rich layered oxide, one of the most promising cathode materials for lithium-ion batteries (LIBs) with high energy density, is suffering from the intrinsic hypersensitivity to moisture and acid gas (CO 2 , SO 2 , etc.) in the environment, leading to the generation and growth of residual lithium compounds (e.g. Li 2 CO 3), accompanied by surficial phase transition, high alkalinity and electrochemical deterioration. Eliminating these negative effects would require considerable energy and manpower, which hinders the promotion of Ni-rich cathode materials. Herein, we introduced crosslinked poly-methylhydrosiloxane (PMHS) and hydroxy‑terminated poly-dimethylsiloxane (denoted as PDMS-OH) hydrophobic film to in situ coat single-crystal LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), isolating its Ni-rich electrode surface from moisture and acid gas to prevent side reactions. Specifically, the desired crosslinking layer, which is optimized by increasing the relative content of PMHS and decreasing the absolute content of PDMS-OH, endows the coated NCM811 with an appreciable improvement in hydrophobicity and storage performances and effectively suppresses the formation and growth of residual lithium compounds on the surface of NCM811 particles in a simulated damp-heat storage environment. Simultaneously, the crosslinked coating diminished the extraction of Li and Ni during exposure and maintained the high electrochemical performance of NCM811. This proposed strategy to crosslink polysiloxane film on the surface of Ni-rich cathode materials greatly alleviates the problem of storage failure, which will promote the practical popularization of Ni-rich cathode materials in LIBs. In situ crosslinked polysiloxanes coating layer endows surface of Ni-rich oxide cathode material with appreciable and durable hydrophobicity, successfully improving the ability of Ni-rich oxide cathode to resist severe environments and preventing electrochemical deterioration from side reactions induced by H 2 O or other acid gasses. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract We present a layered-carbon/PbSO 4 composite additive for the negative active material (NAM) of lead-acid batteries to improve their high rate charge/discharge performance. The layered-carbon/PbSO 4 composite, consisting of graphene-like two-dimensional carbon decorated with fine PbSO 4 particles, is prepared by a simple chemical vapor deposition (CVD) method and a subsequent ion exchange process. In the synthesis process, potassium carbonate functions as template to promote the generation of layered carbon sheets in CVD process and as template in ion exchange process to in situ produce PbSO 4 nanoparticles. The composite can effectively enhance the electronic conductivity and the ionic conductivity of NAM, and resist the tendency to sulfation during high-rate partial-state-of-charge (HRPSoC) operation. Moreover, the PbSO 4 deposits on the layered-carbon can not only make the carbonaceous additive be uniformly mixed with the NAM, but also inhibit the hydrogen evolution of the layered-carbon. As a result, the specific capacity, rate performance, and HRPSoC cycling performance of the NAM are significantly enhanced. The NAM with 2 wt% composite additive (the content of layered-carbon in NAM is 0.1 wt%) delivers a high initial specific discharge capacity of 160 mAh g−1 at 0.1 C rate, and 61 mAh g−1 at a high rate of 10 C rate, which is 30% higher than that of the Ref one. The cell with composite additives has achieved a HRPSoC cycle life of 160,000 cycles, which is 3 times longer than the Ref cell. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

The effect of activated carbon (AC) surface functional groups on the cycle performance of lead-carbon batteries was studied from hydrogen evolution and nano-lead electrodeposition on the surface of the AC. AC materials were modified by oxidation methods (hot air or acid treatment) to increase acidic groups and reduction processes (alkaline treatment or heat treatment in N 2 ) to increase alkaline groups. The surface functional groups were characterized by X-ray photoelectron spectroscopy and Boehm titration method. We used cyclic voltammetry and a three-electrode system to prepare nano-lead deposits on the surface of the AC, and studied its influence on hydrogen evolution of AC. The results show that acidic groups are beneficial to lead electrodeposition. In addition, the lead deposits with high activity covering the surface of AC could inhibit hydrogen evolution and the irreversible sulfation in lead-carbon batteries, and then result in longer cycle life under High-rate Partial-state-of-Charge conditions. [ABSTRACT FROM AUTHOR]

Capacitive lithium-ion batteries with a dual-energy storage mechanism can provide a high energy and power density, which are constructed by the addition of slightly porous carbon. Here, the effect from porous carbon, such as the proportion, specific surface area, pore size and electrical conductivity, on the rate performance is systematically studied using hybrid electrodes with LiNi 0.6 Co 0.2 Mn 0.2 O 2 and activated carbon or carbon aerogel. Compared with LiNi 0.6 Co 0.2 Mn 0.2 O 2 electrodes, the hybrid electrodes demonstrate a lower resistivity, smaller electrochemical polarization, stronger rate capability and stable capacity retention. Furthermore, Adding carbon aerogel into LiNi 0.6 Co 0.2 Mn 0.2 O 2 material is more conducive to enhancing the rate performance when compared with activated carbon. The lithium-ion full capacitor battery configured of a hard carbon anode and LiNi 0.6 Co 0.2 Mn 0.2 O 2 -carbon aerogel delivers a capacity of 97.3 mAhg−1 at 10C with an energy density reaching 323.8 Wh∙kg−1 (vs. the cathode), showing bright prospects in energy storage system with both high specific energy and power densities. [ABSTRACT FROM AUTHOR]

Abstract: A series of polyaniline/carbon nanotube array (PANI/CNTA) composite electrodes are prepared by electrodeposition of PANI onto CNTA electrodes by 100–500 cyclic voltammetry (CV) cycles, with the aim to investigate the influence of microstructure on the capacitive performance of PANI/CNTA composites. The morphology of PANI/CNTA composites varies remarkably with the CV cycles of electrodeposition. The optimum condition is obtained for the PANI/CNTA composite prepared by 100 CV cycles, corresponding to the highest specific capacitance, best rate performance, and longest cycle life, which are much better than that of activated carbon fiber cloth, the PANI electrodeposited on stainless steel substrate, and CNTA electrode. The forming process of the microstructure and its influence on the capacitive performance of PANI/CNTA composites are presented in this paper. [Copyright &y& Elsevier]