Hebei University of Technology

The hole transport layer (HTL)-free carbon-based perovskite solar cells (C-PSCs) are promising for commercialization owing to their excellent operational stability and simple fabrication process. However, the power conversion efficiencies (PCE) of C-PSCs are inferior to the metal electrode-based devices due to their open-circuit voltage (Voc) loss. Herein, time-resolved confocal photoluminescence microscopy reveals that grain boundary defects at the perovskite/carbon interface are very likely to function as nonradiative recombination centers in HTL-free C-PSCs. A versatile additive Li2CO3 is used to modify the conformal tin oxide electron transport layer for HTL-free C-PSCs. Li2CO3 modification can result in enhanced charge extraction and optimized energy alignment at electron transport layer/perovskite interface, as well as suppressed defects at perovskite top surface due to Li2CO3-induced formation of PbI2 crystallites. Such dual interfacial passivation ultimately leads to significantly improved Voc up to 1.142 V, which is comparable to the metal electrode-based devices with HTL. Moreover, a record-high PCE of 33.2% is achieved for Li2CO3-modified C-PSCs under weak light illumination conditions, demonstrating excellent indoor photovoltaic performance. This work provides a practical approach to fabricate low-cost, highly efficient carbon-based perovskite solar cells.

Silicon (Si) has emerged as a prominent candidate for high-energy batteries due to its exceptionally high theoretical capacity and favorable lithiation potential. However, its electrochemical performance at subzero temperatures is significantly hampered by slow ion transport and sluggish ion diffusion processes. Here, we present a weakly solvating electrolyte formulated with 1 M lithium bis(fluorosulfonyl)imide (LiFSI) in a mixture of fluoroethylene carbonate (FEC) / methyl trifluoroacetate (MTFA). This electrolyte is elaborated to enhance the ion desolvation process and facilitate the formation of an anion-coupled fluorinated solvent-derived hybrid solid electrolyte interphase (SEI) on Si anodes, thereby significantly improving the electrochemical performance. Comprehensive characterizations paired with molecular dynamics (MD) calculations reveal that the hybrid SEI consists of an organic outer layer and a lithium fluoride (LiF) and sulfurized species-rich inner layer, which maintain the structural integrity of the electrode while promoting rapid Li⁺ diffusion even at cryogenic temperatures. As anticipated, the Si electrode demonstrates exceptional delivery capacities of approximately 3100-2600 mAh g^-1 at subzero temperatures ranging from 0 °C to -20 °C and a reversible specific capacity of around 2100 mAh g^-1 even at -30 °C.

The machine learning (ML) as an indispensable tool has attracted widespread attention in domestic wastewater treatment processes.However, ML have not been widely utilized in comprehensive prediction of effluent quality and comprehensive environmental impact.In this research, under six ML models, 360 samples were collected to predict effluent quality and comprehensive environmental assessment (CEA) for anaerobic-anoxic-oxic-membrane bioreactor (A²O-MBR) domestic wastewater treatment process.The typical industrial scenario anal. indicated that the environmental impact could be decreased under the hydraulic retention time of 4-10 h, and nitrox reflux ratio in 50 %-200 %, when the influent total phosphorus in 1-2 mg/L, influent COD in 100-120 mg/L, influent ammonium in 10-18 mg/L.Meanwhile, a comprehensive index prediction model was developed, demonstrating that the extreme gradient boosting model has better fitting performance coefficient of determination with 0.8053.This research offers the foundation for the efficient and stable operation and environmental impacts of the wastewater treatment process.