With rapid progress in a power conversion efficiency (PCE) to reach 25%, metal halide perovskite-based solar cells became a game-changer in a photovoltaic performance race. Triggered by the development of the solid-state perovskite solar cell in 2012, intense follow-up research works on structure design, materials chemistry, process engineering, and device physics have contributed to the revolutionary evolution of the solid-state perovskite solar cell to be a strong candidate for a next-generation solar energy harvester. The high efficiency in combination with the low cost of materials and processes are the selling points of this cell over commercial silicon or other organic and inorganic solar cells. The characteristic features of perovskite materials may enable further advancement of the PCE beyond those afforded by the silicon solar cells, toward the Shockley-Queisser limit. This review summarizes the fundamentals behind the optoelectronic properties of perovskite materials, as well as the important approaches to fabricating high-efficiency perovskite solar cells. Furthermore, possible next-generation strategies for enhancing the PCE over the Shockley-Queisser limit are discussed.

High-Efficiency Perovskite Solar Cells.

Mixed metal sulfides (MMSs) have attracted increased attention as promising electrode materials for electrochemical energy storage and conversion systems including lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), hybrid supercapacitors (HSCs), metal–air batteries (MABs), and water splitting. Compared with monometal sulfides, MMSs exhibit greatly enhanced electrochemical performance, which is largely originated from their higher electronic conductivity and richer redox reactions. In this review, recent progresses in the rational design and synthesis of diverse MMS-based micro/nanostructures with controlled morphologies, sizes, and compositions for LIBs, SIBs, HSCs, MABs, and water splitting are summarized. In particular, nanostructuring, synthesis of nanocomposites with carbonaceous materials and fabrication of 3D MMS-based electrodes are demonstrated to be three effective approaches for improving the electrochemical performance of MMS-based electrode materials. Furthermore, some potential challenges as well as prospects are discussed to further advance the development of MMS-based electrode materials for next-generation electrochemical energy storage and conversion systems.

Mixed Metal Sulfides for Electrochemical Energy Storage and Conversion

Review of the use of transition-metal-oxide and conducting polymer-based fibres for high-performance supercapacitors

Over the past several decades, the number of electric vehicles (EVs) has continued to increase. Projections estimate that worldwide, more than 125 million EVs will be on the road by 2030. At the heart of these advanced vehicles is the lithium-ion (Li-ion) battery which provides the required energy storage. This paper presents and compares key components of Li-ion batteries and describes associated battery management systems, as well as approaches to improve the overall battery efficiency, capacity, and lifespan. Material and thermal characteristics are identified as critical to battery performance. The positive and negative electrode materials, electrolytes and the physical implementation of Li-ion batteries are discussed. In addition, current research on novel high energy density batteries is presented, as well as opportunities to repurpose and recycle the batteries.

Current Li-Ion Battery Technologies in Electric Vehicles and Opportunities for Advancements

Metal–organic frameworks (MOFs) have obtained increasing attention as a kind of novel electrode material for energy storage devices. Yet low capacity in most MOFs largely thwarts their application. In this study, an effective strategy was developed to improve the conductivity of MOFs by partially substituting Ni2+ in the Ni-MOF with Co2+ or Zn2+. The mixed-metal organic frameworks (M-MOFs) showed excellent electrochemical performance, which is attributed not only to the favorable paths for charge transport due to the presence of free pores, but also to the raised electrochemical double-layer capacitance (EDLC) at the enlarged specific surface area of the material. Meanwhile, the cycling stability of the assembled hybrid supercapacitors (M-MOFs//CNTs–COOH) is enhanced due to the alleviation of phase transformation during electrochemical cycling tests. More interestingly, the Co/Ni-MOF//CNTs–COOH also exhibited an excellent energy density (49.5 W h kg−1) and power density (1450 W kg−1) simultaneously. These values demonstrated the better performance of all the MOF materials in supercapacitors at present. In addition to broadening the application of MOFs, our study may open a new avenue for bridging the performance gap between batteries and supercapacitors.

Mixed-metallic MOF based electrode materials for high performance hybrid supercapacitors

A high energy density aqueous hybrid supercapacitor with widened potential window through multi approaches

Despite the low-cost and moderate-temperature fabrication process of inverted planar perovskite solar cells (PVSCs), the relatively low efficiency (<20%), inferior reproducibility and poor stability significantly hinder their great potential for future commercialization. To address these issues, here we introduce a novel, economic and efficient hydrophilic group (C–O & CO) grafted buffer layer (HGGBL) on a non-wetting hole transporting material (HTM) for perovskite formation. This approach of introducing the buffer layer with grafted hydrophilic groups leads to a decrease in the surface potential and surface tension force of the non-wetting HTM, facilitating the nucleation and growth of perovskite crystals. Also importantly, the carbonyl groups tightly bond with the perovskite via Lewis base sites, leading to a dense, smooth, pinhole-free perovskite film with bulk defects being passivated. Benefiting from these merits, the photovoltaic performance is dramatically boosted from 17.42% to 20.75%, which is among the highest efficiencies of inverted planar PVSCs. In addition, the PVSCs with the HGGBL exhibit excellent reproducibility with negligible hysteresis and superior humidity stability. This work validates that the HGGBL is a promising approach for growing perovskite films on non-wetting layers for both high-performance solar cells and other optoelectronic devices.

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20.7% highly reproducible inverted planar perovskite solar cells with enhanced fill factor and eliminated hysteresis

Super long-life all solid-state asymmetric supercapacitor based on NiO nanosheets and α-Fe2O3 nanorods

The rapid advance of mild aqueous zinc-ion batteries (ZIBs) is driving the development of the energy storage system market. But the thorny issues of Zn anodes, mainly including dendrite growth, hydrogen evolution, and corrosion, severely reduce the performance of ZIBs. To commercialize ZIBs, researchers must overcome formidable challenges. Research about mild aqueous ZIBs is still developing. Various technical and scientific obstacles to designing Zn anodes with high stripping efficiency and long cycling life have not been resolved. Moreover, the performance of Zn anodes is a complex scientific issue determined by various parameters, most of which are often ignored, failing to achieve the maximum performance of the cell. This review proposes a comprehensive overview of existing Zn anode issues and the corresponding strategies, frontiers, and development trends to deeply comprehend the essence and inner connection of degradation mechanism and performance. First, the formation mechanism of dendrite growth, hydrogen evolution, corrosion, and their influence on the anode are analyzed. Furthermore, various strategies for constructing stable Zn anodes are summarized and discussed in detail from multiple perspectives. These strategies are mainly divided into interface modification, structural anode, alloying anode, intercalation anode, liquid electrolyte, non-liquid electrolyte, separator design, and other strategies. Finally, research directions and prospects are put forward for Zn anodes. This contribution highlights the latest developments and provides new insights into the advanced Zn anode for future research. 

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Zinc Anode for Mild Aqueous Zinc-Ion Batteries: Challenges, Strategies, and Perspectives

https://link.springer.com/content/pdf/10.1007/s40820-021-00782-5.pdf

Si-Wen Zhang

Papers

A high energy density aqueous hybrid supercapacitor with widened potential window through multi approaches

20.7% highly reproducible inverted planar perovskite solar cells with enhanced fill factor and eliminated hysteresis

Super long-life all solid-state asymmetric supercapacitor based on NiO nanosheets and α-Fe2O3 nanorods

Zinc Anode for Mild Aqueous Zinc-Ion Batteries: Challenges, Strategies, and Perspectives

Zinc Anode for Mild Aqueous Zinc-Ion Batteries: Challenges, Strategies, and Perspectives