Lithium metal anodes have attracted extensive attention owing to their high theoretical specific capacity. However, the notorious reactivity of lithium prevents their practical applications, as ...evidenced by the undesired lithium dendrite growth and unstable solid electrolyte interphase formation. Here, we develop a facile, cost-effective and one-step approach to create an artificial lithium metal/electrolyte interphase by treating the lithium anode with a tin-containing electrolyte. As a result, an artificial solid electrolyte interphase composed of lithium fluoride, tin, and the tin-lithium alloy is formed, which not only ensures fast lithium-ion diffusion and suppresses lithium dendrite growth but also brings a synergistic effect of storing lithium via a reversible tin-lithium alloy formation and enabling lithium plating underneath it. With such an artificial solid electrolyte interphase, lithium symmetrical cells show outstanding plating/stripping cycles, and the full cell exhibits remarkably better cycling stability and capacity retention as well as capacity utilization at high rates compared to bare lithium.
Energy for a sustainable future motivates today's R&D, enabling technologies such as smart consumer electronics, electric vehicles, and smart grids. These technologies demand the use of batteries. ...Sunlight, an abundant clean source of energy, can alleviate the energy limits of batteries, while batteries can address photovoltaic intermittency. This perspective paper focuses on advancing concepts in PV-battery system design while providing critical discussion, review, and prospect. Reports on discrete and integrated PV-battery designs are discussed. Three key technical challenges, namely energy density, efficiency, and stability, toward further advancement of integrated PV-battery systems are discussed. We present a perspective on opportunities and future directions, highlighting key strategies on developing such PV-battery systems. Key focus should be on the development of innovative designs that incorporates high-capacity, efficient, and stable materials, emphasizing the demonstration of practical viability of such integrated PV-battery systems.
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Today's world is energy driven and batteries have become an integral part as an energy source considering the technological advances in consumer electronics to electric vehicles, renewables, and smart grids. Batteries are energy limited and require recharging. Recharging batteries with solar energy by means of solar cells can offer a convenient option for smart consumer electronics. Meanwhile, batteries can be used to address the intermittency concern of photovoltaics.
This perspective discusses the advances in battery charging using solar energy. Conventional design of solar charging batteries involves the use of batteries and solar modules as two separate units connected by electric wires. Advanced design involves the integration of in situ battery storage in solar modules, thus offering compactness and fewer packaging requirements with the potential to become less costly. This advancement can be advantageous for consumer electronics where space, size, and packaging requirements hold greater value. Three major metrics, namely energy density, efficiency, and stability, have been addressed by presenting relevant challenges and potential opportunities. The integrated design is still in the early R&D phase. There is a need for innovative designs that explore high-capacity, efficient, and stable materials. Meanwhile, to demonstrate its practical viability, this integrated design should also focus on real-world applications such as wearables that demand specific requirements of energy and power.
This perspective provides insights into battery-charging designs using solar energy. Advances in conventional-discrete-type and advanced-integrated-type systems are summarized. Three key challenges of such integrated-type systems, namely energy density, overall efficiency, and stability, are discussed while presenting potential opportunities to overcome them. Finally, the perspective provides some practical considerations that would guide future efforts.
Dye sensitized solar cells (DSCs) provide a low cost alternative to silicon solar cells due to their low material and fabrication cost. Usually DSCs utilize platinum to catalyze the iodine redox ...couple and complete the electric circuit. Since platinum is rare and expensive metal, nanostructured carbonaceous materials have been widely investigated as a promising alternative to replace it. Carbon nanostructures have shown significant properties such as high electrochemical activity, high corrosion resistance, and low cost which make them ideal for replacing platinum in the counter electrodes of DSCs. Here we reviewed the development in carbon based counter electrodes which utilize the advantages of high surface area and high electrocatalytic ability due to their nanostructured morphology. First, various carbon nanostructures including graphene, carbon nanotubes, carbon nanofibers, carbon nanoparticles, conductive carbon, carbon dye and composite carbon nanostructures are introduced. Second, carbon nanostructured counter electrode morphologies and their effects on DSC performance are discussed. Third, surface defects and their effects on cell performance are described. Finally, equivalent circuit models at the counter electrode–electrolyte interface are presented. This work will provide deep insights and guidance for researchers to design, develop and/or select carbon nanostructures for cost effective Pt-free or less-Pt loaded DSCs.
Carbon nanostructures including nanofibers, nanoparticles, nanotubes, graphene, and their composites with metallic nanoparticles are used as low cost counter electrode in dye-sensitized solar cells. Display omitted
•Reviewed recent progress on carbon nanostructures as counter electrodes for dye-sensitized solar cells.•Discussed the effects of morphology, surface defects, and functional groups on the electrocatalytic properties of carbon electrodes.•Described various equivalent electrical circuit models that represent the carbon–electrolyte interface.•Provided deep insights and guidance for researchers to design, develop and/or select carbon nanostructures for cost effective Pt-free or less-Pt loaded DSCs.
Earth abundant kesterite copper-zinc-tin-sulfide-selenide (CZTS-Se) is considered as cost-effective material for next generation solar cells. However, current CZTS-Se solar cells have much lower ...efficiency than CIGS solar cells. Rapid progress in achieving the target efficiency in CZTS-Se solar cells is hindered by the narrow phase stability of the quaternary phase, Cu
2
ZnSn(S
x
Se
1−
x
)
4
, and the existence of other competitive and complex secondary phases and defects. This resulted in structural inhomogeneity, local fluctuation of open circuit voltage and high carrier recombination that finally lead to poor device performance and repeatability issues. The higher performance of off-stoichiometric CZTS materials, copper-poor and zinc-rich, and their inherent association with secondary phases and defects force the scientific community to investigate them together. This work aims to provide a comprehensive review for optimum growth conditions to achieve efficient kesterite CZTS-Se material under different conditions, complementary characterization techniques to detect unwanted phases, defects and defect-complexes and various approaches to reduce the secondary phases, defects and defect-complexes for higher performance in CZTS-Se solar cells. Understanding and addressing the structural inhomogeneity, control growth and material characterization are expected to yield closer performance parity between CZTS-Se and CIGS solar cells.
This article presents a strategic review of secondary phases, defects and defect-complexes in kesterite CZTS-Se solar cells responsible for performance gap from CIGS solar cells.
An organic-inorganic perovskite is comprised of an organic cation (CH
3
NH
3
+
, FAI, or Cs), a metal cation (Pb
2+
or Sn
2+
) and a halide (I
−
, Cl
−
, or Br
−
) molecule. Precursor salts ...containing these cations, molecules and halide ions dissolved in solvents are used to prepare perovskite films. Perovskite film formation takes place through the reaction of precursor elements, which is assisted by various processing conditions such as thermal annealing, moisture and solvent treatment. This review focuses on various perovskite formation and crystallization routes with respect to processing parameters including the precursor solvent, solvent mixture, temperature, time, formation of solvent led-intermediate complex species, doping and humidity. Adding water as the dopant to the precursor solvent and exposure to moisture from atmospheric humidity to improve perovskite film quality are also discussed. Processing conditions and crystallization processes are described in correlation with the perovskite film morphology, crystallinity, defects, charge transport and device performance. This article will aim to highlighting recent findings in the selection of solvents in the crystallization of perovskite films, solvent induced intermediate phases, and effects of water in assisting perovskite crystallization for improved film quality and device performance. The review will also present various structural and nanoscale characterization techniques that have been used to probe solvent based intermediate species transformation processes to the perovskite phase and understand the effects in correlation with device performance.
An organic-inorganic perovskite is comprised of an organic cation (CH
3
NH
3
+
, FAI, or Cs), a metal cation (Pb
2+
or Sn
2+
) and a halide (I
−
, Cl
−
, or Br
−
) molecule.
Lithium (Li) metal has been considered as one of the most attractive anode materials of Li batteries due to its high theoretical capacity and low electrochemical potential. However, dendrite ...formation and large volume change during battery operation hinder its commercialization. Here, we created a three-dimensional (3D) light-weight and mechanically flexible copper-clad carbon framework (CuCF) as a lithiophilic current collector. The CuCF can be made by scalable pyrolysis of a melamine-formaldehyde foam (MF) followed by copper electroplating. The carbon framework (CF) without copper cladding has a lower conductivity (4.32 × 10
−4
S cm
−1
) and fewer non-uniform lithium nucleation sites, leading to lithium dendrite growth during plating/stripping. By surface engineering with copper-cladding, the CuCF has a much higher conductivity (1.38 × 10
−2
S cm
−1
) and more Li nucleation sites which allow a uniform and smooth Li deposition. Moreover, the excellent mechanical flexibility and enlarged surface area of the CuCF current collector can accommodate volume expansion and reduce local current density. As a result, a dendrite-free Li metal anode is achieved with a high coulombic efficiency of 99.5% even after 300 plating/stripping cycles (∼1200 hours). Significantly, it can last for more than 170 cycles at a high current of 5 mA cm
−2
in a symmetric cell cycling test. Furthermore, a Li/lithium iron phosphate (LFP) cell exhibits a long cycling life at a high current of 1C.
A flexible copper-clad lithiophilic current collector was designed for high coulombic efficiency dendrite-free Li metal anodes.
Polymer aggregation and crystallization behavior play a crucial role in the performance of all-polymer solar cells (all-PSCs). Gaining control over polymer self-assembly via molecular design to ...influence bulk-heterojunction active-layer morphology, however, remains challenging. Herein, we show a simple yet effective way to modulate the self-aggregation of the commonly used naphthalene diimide (NDI)-based acceptor polymer (N2200), by systematically replacing a certain amount of alkyl side-chains with compact bulky side-chains (CBS). Specifically, we have synthesized a series of random copolymer (PNDI-CBS x ) with different molar fractions (x = 0–1) of the CBS units and have found that both solution-phase aggregation and solid-state crystallinity of these acceptor polymers are progressively suppressed with increasing x as evidenced by UV–vis absorption, photoluminescence (PL) spectroscopies, thermal analysis, and grazing incidence X-ray scattering (GIWAXS) techniques. Importantly, as compared to the highly self-aggregating N2200, photovoltaic results show that blending of more amorphous acceptor polymers with donor polymer (PBDB-T) can enable all-PSCs with significantly increased PCE (up to 8.5%). The higher short-circuit current density (J sc) results from the smaller polymer phase-separation domain sizes as evidenced by PL quenching and resonant soft X-ray scattering (R-SoXS) analyses. Additionally, we show that the lower crystallinity of the active layer is less sensitive to the film deposition methods. Thus, the transition from spin-coating to solution coating can be easily achieved with no performance losses. On the other hand, decreasing aggregation and crystallinity of the acceptor polymer too much reduces the photovoltaic performance as the donor phase-separation domain sizes increases. The highly amorphous acceptor polymers appear to induce formation of larger donor polymer crystallites. These results highlight the importance of a balanced aggregation strength between the donor and acceptor polymers to achieve high-performance all-PSCs with optimal active layer film morphology.
Carbon-based CsPbBr3 perovskite solar cell is an emerging inorganic perovskite solar cell with the advantages of simple fabrication process and excellent stability. However, power conversion ...efficiency of carbon-based CsPbBr3 perovskite solar cells is still unsatisfactory up to now, as the direct contact of the CsPbBr3 with carbon is plagued with interfacial recombination sites and undesirable hole extraction barrier. Here, we report an effective strategy that employs poly (3-hexylthiophene) (P3HT) to modify the CsPbBr3/carbon interface in carbon-based CsPbBr3 perovskite solar cells and enable higher efficiency. The systematic tests and analyses demonstrate that the P3HT interlayer can remarkably suppress the charge recombination and enhance the hole extraction capability via formation of favorable energy level alignment between CsPbBr3 film and carbon electrode, and passivation of the surface defect states of CsPbBr3 film. As a result, the carbon-based CsPbBr3 perovskite solar cell with P3HT interlayer achieves a high conversion efficiency of 6.49%, exhibiting an increase by 27% compared to pristine device. Moreover, the carbon-based CsPbBr3 perovskite solar cells with P3HT interlayer exhibits excellent stability in ambient air with almost no change in the power conversion efficiency of the unsealed device over 40 days.
•P3HT is employed to modify the CsPbBr3/carbon interface in carbon-based CsPbBr3 PSCs.•P3HT remarkably suppress the charge recombination and enhance the hole extraction.•The device with P3HT shows an efficiency of 6.49%, increasing by 27% over pristine one.
The interfaces between perovskite layer and electrodes play a crucial role on efficient charge transport and extraction in perovskite solar cells (PSCs). Herein, for the first time we applied a ...low-cost nonconjugated polymer poly(vinylpyrrolidone) (PVP) as a new interlayer between PCBM electron transport layer (ETL) and Ag cathode for high-performance inverted planar heterojunction perovskite solar cells (iPSCs), leading to a dramatic efficiency enhancement. The CH3NH3PbI3–x Cl x -based iPSC device incorporating the PVP interlayer exhibited a power conversion efficiency (PCE) of 12.55%, which is enhanced by ∼15.9% relative to that of the control device without PVP interlayer (10.83%). The mechanistic investigations based on morphological, optical, and impedance spectroscopic characterizations reveal that incorporation of PVP interlayer promotes electron transport across the CH3NH3PbI3–x Cl x perovskite/Ag interface via PCBM ETL. Besides, PVP incorporation induces the formation of a dipole layer, which may enhance the built-in potential across the device, conjunctly promoting electron transport from PCBM to Ag cathode and consequently leading to significantly improved fill factor (FF) from 58.98 to 66.13%.
In recent years, hybrid perovskite solar cells (HPSCs) have received considerable research attention due to their impressive photovoltaic performance and low‐temperature solution processing ...capability. However, there remain challenges related to defect passivation and enhancing the charge carrier dynamics of the perovskites, to further increase the power conversion efficiency of HPSCs. In this work, the use of a novel material, phenylhydrazinium iodide (PHAI), as an additive in MAPbI3 perovskite for defect minimization and enhancement of the charge carrier dynamics of inverted HPSCs is reported. Incorporation of the PHAI in perovskite precursor solution facilitates controlled crystallization, higher carrier lifetime, as well as less recombination. In addition, PHAI additive treated HPSCs exhibit lower density of filled trap states (1010 cm−2) in perovskite grain boundaries, higher charge carrier mobility (≈11 × 10−4 cm2 V−1 s), and enhanced power conversion efficiency (≈18%) that corresponds to a ≈20% improvement in comparison to the pristine devices.
A novel material called phenylhydrazinium iodide (PHAI) is effective for defects minimization, surface passivation, and efficient charge transportation in hybrid perovskite solar cells. It plays multiple roles in controlled crystallization, stabilizing under‐coordinated ions, and as a self‐supported moisture barrier in perovskite films.
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