High electrochemical stability and reaction kinetics of Zn anodes are crucial for rechargeable aqueous zinc batteries. Developing low-cost aqueous electrolytes is highly required. In this work, the fundamental principles to improve Zn anodes are systematically revealed in low-cost 1 M ZnSO 4 -based aqueous electrolytes using trace polymer additives with different polarities. The functional polymer additive could rearrange the "Zn 2+ −H 2 O−SO 4 2− −polymer" bonding network accordingly and reconstruct the space charge region of Zn anodes, resulting in distinctive cycling stability and reaction kinetics. Polymers with moderate polarity, such as polyacrylamide, exhibit synergic enhancement as the "smoother" and "thruster" for Zn 2+ toward Zn anodes, with which Zn anodes run over 1300 h with Coulombic efficiency >99.65% under 2 mA cm −2 , 2 mAh cm −2 , showing uniform Zn deposition with minimal impact on reaction kinetics. This work provides useful insights on designing low-cost and high-performance aqueous electrolytes through functional electrolyte additives.
Mild aqueous Zn batteries have attracted increasing attention for energy storage due to the advantages of high safety and low cost; however, the rechargeability of Zn anodes is one major issue for practical applications. In this work, an effective approach is proposed to improve the reversibility and stability of Zn anodes using advanced acidic electrolytes. A trace amount of acetic acid (HAc) is employed as a buffering agent to provide a stable pH environment in aqueous Zn electrolytes, and thus suppress passivation from precipitation reactions on Zn electrodes. Meanwhile, tetramethylene sulfone (TMS) is introduced as the critical component to stabilize the Zn anodes in the acidic electrolyte. TMS greatly strengthens the hydrogen‐bonding network with reduced H2O activity and extends the electrochemical window of acidic electrolytes. With the optimal 3 m Zn(OTF)2 in (H2O‐HAc)/TMS acidic electrolyte (pH 1.6), the Zn electrode exhibits a coulombic efficiency of >99.8% and smooth Zn deposition. The Zn‐V2O5 full cell demonstrates ultra‐stable cycling over 20 000 cycles with a low decay rate of 0.0009% for each cycle at a negative/postive capacity ratio of 6.5. This work provides an insightful perspective to stabilize Zn electrodes by regulating the pH environment and limiting the H2O activity simultaneously for long‐life Zn anodes.
Challenges remain hindering the performance and stability of inverted perovskite solar cells (PSCs), particularly for the nonstable interface between lead halide perovskite and charge extraction metal oxide layer. Herein, a simple yet scalable interfacial strategy to facilitate the assemble of high‐performance inverted PSCs and scale‐up modules is reported. The hybrid interfacial layer containing self‐assembly triphenylamine and conjugated poly(arylamine) simultaneously improves the chemical stability, charge extraction, and energy level alignment of hole‐selective interface, meanwhile promoting perovskite crystallization. Consequently, the correspondent inverted PSCs and modules achieve remarkable power conversion efficiencies (PCEs) of 24.5% and 20.7% (aperture area of 19.4 cm2), respectively. The PSCs maintain over 80% of its initial efficiency under one‐sun equivalent illumination of 1200 h. This strategy is also effective to perovskite with various bandgaps, demonstrating the highest PCE of 19.6% for the 1.76‐eV bandgap PSCs. Overall, this work provides a simple yet scalable interfacial strategy for obtaining state‐of‐the‐art inverted PSCs and modules.
Composite hydrogels of graphitic carbon nitride nanosheets (CNNS) and polyacrylamide (PAM) with superior UV absorption and visible transparence capabilities are reported. CNNS is employed not only as a photocatalytic initiator to trigger the polymerization of acrylamide, but also as a cross‐linker to 3D connected PAM chains via hydrogen bonds. The obtained CNNS/PAM hydrogels are highly moldable for preparing various forms, and have good mechanical properties, self‐healing ability, and photo‐stability. Furthermore, the composite hydrogels have a wide spectral range for UV absorption compared to conventional UV protective materials. Besides the complete screening of UVB (280–315 nm) in sun radiation, the CNNS/PAM hydrogel film can also filter >95% UVA radiation (315–400 nm) by regulating the coating thickness, meanwhile retaining a high visible transmittance. Therefore, the CNNS/PAM hydrogels have potential applications for shielding UV radiation. Additionally, this strategy provides a common and facile route to fabricate functional composite hydrogels via photo‐induced polymerization.
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