Solar Energy Conversion Systems Research Articles

ARTIFICIAL INTELLIGENCE TECHNIQUE BASED MPPT CONTROLLER FOR STANDALONE SOLAR ENERGY CONVERSION SYSTEM

This paper presents the development and performance analysis of Artificial Intelligence Technique based MPPT controller for a standalone solar energy conversion system. The proposed system consists of 2.5 kW PV array, DC to DC boost converter, inverter and different load. The DC to DC Converter connected to Inverter through DC link capacitor. The inverter power fed to the load through step down transformer. The standalone solar energy conversion system consists of MPPT controller. In this research Artificial Intelligence Technique based MPPT controller on Levenberg algorithm developed. For the proposed Artificial Intelligence Technique based MPPT takes two variables as PV voltage and PV current as an input and output the duty ratio for DC to DC boost converter. The Artificial Intelligence Technique based MPPT controller for standalone solar energy conversion system with various load is modeled and simulated in MATLAB/ Simulink environment. Performance of both the Artificial Intelligence Technique based MPPT controller compared with conventional incremental conductance MPPT. Simulation results show that for a wide range of input irradiance, Artificial Intelligence Technique based MPPT controller shows improved performance than the conventional incremental conductance MPPT with at various operating conditions.

An experimental investigation on the solar–thermal energy conversion performance of Fe 2 O 3 nanofluid with the focus on nanoparticles shape and concentration

Today, the application of nanoparticles with controlled morphologies in solar energy conversion and storage systems is highlighted. This study focused on the assessment of Fe2O3 water-based nanofluids in volumetric solar absorbers and compared the performance of three shapes (blade, spherical, and octahedral), and three concentrations of nanoparticles (0.005, 0.01, and 0.02 vol%). First, a set of homogeneous nanofluids were prepared using a probe ultrasonic apparatus and by adding an anionic surfactant. In addition to long-time stability and narrow particles size distribution, obtained nanofluids presented a considerable light absorption capability in the visible region. It was seen that the light absorption spectrum was broadened with increasing the nanofluid concentration. Moreover, for each concentration, the blade nanoparticles improved the extinction coefficient and the solar-weighted absorption fraction relatively higher than the other shapes. For example, at a concentration of 0.02 vol% and penetration distance of 1 cm, the blade-nanofluid absorbed 96.2% of incident solar energy, which was higher than the spherical nanofluid with 93.5% and octahedral nanofluid with 87.2%. The results of thermal tests conducted in a set of bath direct solar collectors showed that the highest solar–thermal conversion efficiency after 1 hour of light exposure was related to 0.02% blade-nanofluid (82%). In these conditions, the growth of bulk temperature was observed 2.31 times higher than pure water.

Design and development of a low-cost system to convert solar thermal energy into electricity for households in South Africa using solar concentrators

South Africa is, due its specific latitude location in the southern hemisphere, exposed to high solar irradiation levels. Black thermal absorbers have a high absorbance for solar incident radiation, while commercial photovoltaic technology only converts about 10% of energy available in the solar spectrum. In this article, low-cost Peltier conversion cells, that are normally used for cooling purposes, and that are freely available in supply stores in South Africa, were identified as suitable conversion cells for converting thermal energy into electricity. Two prototypes of thermal-to-electricity energy conversion systems were subsequently designed and developed. Particularly, advanced pulse mode DC- to- DC conversion technology, a special electronic control system, was developed, that could extract high amounts of electrical energy from the cells and could store the energy in standard storage batteries. A 3 W and a 30 W output continuous conversion capacity system were developed. A power conversion of up to 2 W capacity per individual cell was achieved. The systems used no movable parts, and the lifespan of the systems is projected to be at least twenty years. Cost and viability analyses of the systems were performed and the results were compared to existing solar photovoltaic energy conversion systems. Combining the 30 W capacity system with a black body and reflector plate absorber system revealed a cost structure of only ZAR 0.8 per kWh, as compared with a derived ZAR 3 per kWh for a combined photovoltaic and solar geyser combination, as calculated for a ten-year term. The technology as developed is suitable to be incorporated in South African households and rural Africa applications.

A hybrid optimization technique for proficient energy management in smart grid environment

Electrical energy is one of the key components for the development and sustainability of any nation. India is a developing country and blessed with a huge amount of renewable energy resources still there are various remote areas where the grid supply is rarely available. As electrical energy is the basic requirement, therefore it must be taken up on priority to exploit the available renewable energy resources integrated with storage devices like fuel cells and batteries for power generation and help the planners in providing the energy-efficient and alternative solution. This solution will not only meet electricity demand but also helps reduce greenhouse gas emissions as a result the efficient, sustainable and eco-friendly solution can be achieved which would contribute a lot to the smart grid environment. In this paper, a modified grey wolf optimizer approach is utilized to develop a hybrid microgrid based on available renewable energy resources considering modern power grid interactions. The proposed approach would be able to provide a robust and efficient microgrid that utilizes solar photovoltaic technology and wind energy conversion system. This approach integrates renewable resources with the meta-heuristic optimization algorithm for optimal dispatch of energy in grid-connected hybrid microgrid system. The proposed approach is mainly aimed to provide the optimal sizing of renewable energy-based microgrids based on the load profile according to time of use. To validate the proposed approach, a comparative study is also conducted through a case study and shows a significant savings of 30.88% and 49.99% of the rolling cost in comparison with fuzzy logic and mixed integer linear programming-based energy management system respectively.

Experimental study on the thermal performance of a flat plate solar water collector with a bifunctional flow insert

A flat plate solar water collector is a simple solar energy conversion system for hot water production. In this experimental work, the effect of bifunctional rectangular cut flow deviator longitudinal flow inserts with a tilt angle of 30° fixed inside the absorber tube is studied with different water flow rates (0.0083, 0.0167, and 0.025 kg/s). The maximum instantaneous efficiency obtained is 72.93% at 0.025 kg/s, which is 23.6% higher than that of the conventional collector, and a lower mass flow rate results in better exergy efficiency of 3.3% at 0.0083 kg/s. The maximum instantaneous efficiency for a modified collector is observed when the outlet water temperature of 56.7 °C and the proposed flow inserts result in a maximum temperature difference of 10.5 °C between the water inlet and outlet points. The flow inserts serve as a turbulence promoter to enhance the heat transfer coefficient and the heat absorption rate of a conventional collector. The significant contribution of the flow inserts towards increasing the instantaneous efficiency of the collector confirms the bifunctionality with minimum pressure drop and pumping power. The enviro-economic analysis ensures a clean production, and solar collectors with passive inserts provide a lower payback period due to higher thermal energy output. The proposed collector's annual CO₂ mitigation and carbon credit are higher than the conventional collector, and such collectors are feasible for commercialization.

Power Quality Improvement of a Solar Energy Conversion System by a Coordinated Active and LCL Filtering

Power converters play an essential role in Photovoltaic (PV) system to maximize the power transfer to the electrical grid. However, the generated harmonics in the grids due to these power converters and nonlinear loads are considered one of the encountered problems to overcome. This paper presents a decoupled control of PV field real power and reactive power injected to the high voltage network via a PWM inverter by using fuzzy logic controllers. Elsewhere, a procedure based on a coordinated active and LCL filtering is proposed to mitigate the harmonic current introduced by a nonlinear load and the inverter itself in such a way to enhance the power quality injected into the grid. The results obtained in the present study show the good performance of the suggested hybrid filtering approach and demonstrate that almost all harmonics orders of the grid current are well mitigated; the current Total Harmonic Distortion (THD) meets its standard and consequently the power quality is considerably enhanced.

Constructal design for flat plate collector in a solar ocean thermal energy conversion system

<p indent=0mm>Collectors are important components for heat collection in solar ocean thermal energy conversion (OTEC) systems. In the present study, a complex function composed of the linear weighted sum of the seawater outlet temperature and the total consumed pumping power is established. Under the conditions of fixed total volumes of the heat absorption plate and the heat exchange tube, constructal optimization of a flat plate solar collector is conducted by taking the complex function as the optimization objective. The minimum complex function and optimal inner diameter of the heat exchange tube are obtained. The results show that compared with those obtained for the initial design point, the total consumed pumping power and complex function of the solar collector after constructal optimization are reduced by 66.89% and 5.56%, respectively, and the seawater outlet temperature is reduced by 8.9%. This illustrates that although the complex function sacrifices a certain amount of heat transfer performance, the flow performance is greatly improved, as is the overall performance of the flat plate collector. The minimum complex function decreases with increases in the single plate width, solar radiation intensity, seawater outlet temperature, thermal conductivity of the heat absorption plate, and number of collector units, and a decrease in the total seawater mass flow rate. Constructal theory is applied for constructal optimization of the flat plate solar collector, which provides new guidelines for its structural optimization design. This method can be further extended to the optimal designs of solar OTEC systems.

A comparative study for selecting more efficient black selective coating in solar water heating system

Solar thermal collector represents a common system for efficient solar energy conversion. In the field of solar panels, there are numerous types of coatings, their absorptivity is almost more than 90%. The challenge now is to lower the heat loss through emissivity as it predicts the ultimate efficiency (i.e. performance). The solar selective coating is showing higher solar absorption efficiency compared to the commercial black paint, that are applied in most usual solar water heating systems. The present research is devoted to test two types of coatings: second anodized aluminum and traditional matte black paint. Two prototypes of solar water heating system were designed, one having aluminum solar panel coated by matte black paint and the other including solar panel of anodized aluminum electrolytically colored by tin metal ions after two steps of anodization. The second anodized was found to be superior. The calculated performance or efficiency was about 62%. The efficiency of matte black paint was less than the second anodized type. Moreover, the performance without collector glass cover is lowered drastically

A Spontaneous Control for Grid Integrated Solar Photovoltaic Energy Conversion Systems With Voltage Profile Considerations

This work introduces an anti-windup feedback second order generalized integrator (AWFSOGI) based direct power control for voltage source converter (VSC) in the grid integrated solar photovoltaic energy conversion system, for dynamic control of active and reactive powers fed into the grid. The primary aim of the control is to extract fundamental component from distorted grid conditions and to feed the power to the grid at UPF in the course of normal conditions. The control can also work towards maintaining the voltage profile by regulating the phase voltage with the help of reactive power injection and functioning a ride through operation. During all these operations, no trade-off occurs with the system power quality. The efficacy of the technique is shown in simulation and exemplified experimentally under adverse grid conditions. Under all these situations, the harmonics are well within limits according to the IEEE standard-519.

Photovoltaic Energy Conversion Systems with Sliding Mode Control

A new sliding-mode-control-based power conversion scheme is proposed for photovoltaic energy conversion systems. The perturbation and observation (P&amp;O) maximum power-point tracking (MPPT) approach is adopted for optimizing the power generation capabilities from solar panels. Due to the inherent nonlinear dynamics of power converters, we need to adopt a nonlinear control approach to optimize the energy conversion efficiency and tolerate the fluctuations and changes of load and sunlight irradiance. In this manuscript, novel first-and higher-order sliding mode control approaches are proposed, aiming to provide a systematic approach for the robust and optimal control of solar energy conversion, which guarantees Lyapunov stability and consistent performance in the face of external perturbations and disturbances. Moreover, to eliminate the chattering phenomenon inherent in the first-order approach, super-twisting second-order sliding mode control is developed for the buck-boost converter. Furthermore, the output of DC–DC converter supplies a voltage-oriented-control (VOC)-based space-vector pulse-width-modulated inverter to generate three-phase AC power to the grid. To demonstrate the robustness and effectiveness of the proposed scheme, computer simulations and dSPACE hardware-in-the-loop platform have been carried on for examining the proposed sliding-mode-control-based solar energy conversion system.

Stationary Hybrid Renewable Energy Systems for Railway Electrification: A Review

This article provides an overview of modern technologies and implemented projects in the field of renewable energy systems for the electrification of railway transport. In the first part, the relevance of the use of renewable energy on the railways is discussed. Various types of power-generating systems in railway stations and platforms along the track, as well as in separate areas, are considered. The focus is on wind and solar energy conversion systems. The second part is devoted to the analysis of various types of energy storage devices used in projects for the electrification of railway transport since the energy storage system is one of the key elements in a hybrid renewable energy system. Systems with kinetic storage, electrochemical storage batteries, supercapacitors, hydrogen energy storage are considered. Particular attention is paid to technologies for accumulating and converting hydrogen into electrical energy, as well as hybrid systems that combine several types of storage devices with different ranges of charge/discharge rates. A comparative analysis of various hybrid electric power plant configurations, depending on the functions they perform in the electrification systems of railway transport, has been carried out.

Single-Molecule Measurements Spatially Probe States Involved in Electron Transfer from CdSe/CdS Core/Shell Nanorods

Semiconductor nanorods with charge-accepting molecules adsorbed on their surfaces serve as model systems for solar energy conversion. An electron photoexcited from the valence band of the nanorod to a high-energy state in the conduction band will relax and transfer to a state in the molecule, producing a long-lived charge-separated state that facilitates charge extraction and thereby enables photochemical reactions. Characterizing the dynamics of the charge-separation process and the electronic states involved is essential for a microscopic understanding of photocatalysis involving these materials, but this information is obscured in ensemble measurements due to the random placement of molecules on the nanorod surfaces. Here, we show that measurements on individual CdSe/CdS core/shell nanorods functionalized by single methyl viologen molecules provide information about the distribution of electron-transfer rates from confined states in the nanorods to states in the molecules. By comparing this transfer-rate distribution to the predictions of a tight-binding model, we find that charge transfer most likely involves hot electrons in an excited conduction-band state, rather than electrons that have fully thermalized to the conduction-band edge. The ability to extract hot electrons from semiconductor nanocrystals may help enable energy-efficient photocatalysis, and the single-particle charge-transfer method may serve as a widely applicable tool to probe the spatial distribution of electronic states in nanocrystals.

Solvent and Temperature Effects on Photoinduced Proton-Coupled Electron Transfer in the Marcus Inverted Region.

Concerted proton-coupled electron transfer (PCET) in the Marcus inverted region was recently demonstrated (Science2019, 364, 471–475). Understanding the requirements for such reactivity is fundamentally important and holds promise as a design principle for solar energy conversion systems. Herein, we investigate the solvent polarity and temperature dependence of photoinduced proton-coupled charge separation (CS) and charge recombination (CR) in anthracene–phenol–pyridine triads: 1 (10-(4-hydroxy-3-(4-methylpyridin-2-yl)benzyl)anthracene-9-carbonitrile) and 2 (10-(4-hydroxy-3-(4-methoxypyridin-2-yl)benzyl)anthracene-9-carbonitrile). Both the CS and CR rate constants increased with increasing polarity in acetonitrile:n-butyronitrile mixtures. The kinetics were semi-quantitatively analyzed where changes in dielectric and refractive index, and thus consequently changes in driving force (−ΔG°) and reorganization energy (λ), were accounted for. The results were further validated by fitting the temperature dependence, from 180 to 298 K, in n-butyronitrile. The analyses support previous computational work where transitions to proton vibrational excited states dominate the CR reaction with a distinct activation free energy (ΔG*CR ∼ 140 meV). However, the solvent continuum model fails to accurately describe the changes in ΔG° and λ with temperature via changes in dielectric constant and refractive index. Satisfactory modeling was obtained using the results of a molecular solvent model [J. Phys. Chem. B1999, 103, 9130–9140], which predicts that λ decreases with temperature, opposite to that of the continuum model. To further assess the solvent polarity control in the inverted region, the reactions were studied in toluene. Nonpolar solvents decrease both ΔG°CR and λ, slowing CR into the nanosecond time regime for 2 in toluene at 298 K. This demonstrates how PCET in the inverted region may be controlled to potentially use proton-coupled CS states for efficient solar fuel production and photoredox catalysis.

Recent Advances and Perspectives in Photodriven Charge Accumulation in Molecular Compounds: A Mini Review.

The formation of so-called solar fuels from abundant low-energetic compounds, such as carbon dioxide or water, relies on the chemical elementary steps of photoinduced electron transfer and accumulation of multiple redox equivalents. The majority of molecular systems explored to date require sacrificial electron donors to accumulate multiple electrons on a single acceptor unit, but the use of high-energetic sacrificial redox reagents is unsustainable. In recent years, an increasing number of molecular compounds for reversible light-driven accumulation of redox equivalents that do not need sacrificial electron donors has been reported. Those compounds are the focus of this mini review. Different concepts, such as redox potential compression (achieved by proton-coupled electron transfer, Lewis acid–base interactions, or structural rearrangements), hybrids with inorganic nanoparticles, and diffusion-controlled multi-component systems, will be discussed. Newly developed strategies to outcompete unproductive reaction pathways in favor of desired photoproduct formation will be compared, and the importance of identifying reaction intermediates in the course of multiphotonic excitation by different time-resolved spectroscopic techniques will be discussed. The mechanistic insights gained from molecular donor–photosensitizer–acceptor compounds inform the design of next-generation charge accumulation systems for solar energy conversion.

Anatase-Wrapped Rutile Nanorods as an Effective Electron Collector in Hybrid Photoanodes for Visible Light-Driven Oxygen Evolution.

Arrays of single crystal TiO2 rutile nanorods (RNRs) appear highly promising as electron-collecting substrates in hybrid photoanodes as the RNRs offer direct charge carriers transport pathways, contrary to the conventional electrodes prepared from TiO2 powders that suffer from the numerous charge traps at the grain boundaries. However, the specific surface area of the nanorods is highly limited by their smooth morphology, which might be detrimental in view of utilizing the RNR as a substrate for immobilizing other functional materials. In this study, we developed a novel anatase-wrapped RNR (ARNR) material fabricated by a facile seed layer-free hydrothermal method. The ARNR comprises polycrystalline anatase nanoparticles formed on the surface of RNR, resulting in a large surface area that provides more deposition sites compared to the bare nanorods. Herein, we functionalize ARNR and RNR electrodes with polymeric carbon nitride (CNx) coupled with a CoO(OH)x cocatalyst for dioxygen evolution. The anatase wrapping of the rutile nanorod scaffold is found to be crucial for effective deposition of CNx and for improved photoanode operation in visible light-driven (λ > 420 nm) oxygen evolution, yielding a significant enhancement of photocurrent (by the factor of ∼3.7 at 1.23 V vs. RHE) and faradaic efficiency of oxygen evolution (by the factor of ∼2) as compared to photoanodes without anatase interlayer. This study thus highlights the importance of careful interfacial engineering in constructing photoelectrocatalytic systems for solar energy conversion and paves the way for the use of ARNR-based electron collectors in further hybrid and composite photochemical architectures for solar fuel production.

The role of carotenoids in proton-pumping rhodopsin as a primitive solar energy conversion system.

Rhodopsin and carotenoids are two molecules that certain bacteria use to absorb and utilize light. Type I rhodopsin, the simplest active proton transporter, converts light energy into an electrochemical potential. Light produces a proton gradient, which is known as the proton motive force across the cell membrane. Some carotenoids are involved in light absorbance and transfer of absorbed energy to chlorophyll during photosynthesis. A previous study in Salinibacter ruber has shown that carotenoids act as antennae to harvest light and transfer energy to retinal in xanthorhodopsin (XR). Here, we describe the role of canthaxanthin (CAN), a carotenoid, as an antenna for Gloeobacter rhodopsin (GR). The non-covalent complex formed by the interaction between CAN and GR doubled the proton pumping speed and improved the pumping capacity by 1.5-fold. The complex also tripled the proton pumping speed and improved the pumping capacity by 5-fold in the presence of strong and weak light, respectively. Interestingly, when canthaxanthin was bound to Gloeobacter rhodopsin, it showed a 126-fold increase in heat resistance, and it survived better under drought conditions than Gloeobacter rhodopsin. The results suggest direct complementation of Gloeobacter rhodopsin with a carotenoid for primitive solar energy harvesting in cyanobacteria.

OPTIMISATION OF SOLAR PHOTOVOLTAIC SYSTEM EMPLOYING DISTRIBUTED MPPT CONTROL

This paper presents simulation and modeling with optimization and analysis in solar photovoltaic systems, as well as the role and potential of maximum power extraction with controller. Matrix calculations for grid inverters with data graphing, their functions, MPPT algorithm applications, user interface design for monitoring PV modules, and interaction with inverter and converter are all aided by simulations of renewable energy systems. It looks at how well they work on a single-phase grid with a PV system. Simulink model for solar energy conversion systems allows you to examine the performance of Photovoltaic cells, modules, arrays, Maximum Power Points and inverters. Controllers are being tracked when the environment and physical variables change. A distributed MPPT scheme, which allows adjustment of each DC-link voltage, may be adopted for PV systems to achieve maximum PV module usage and solar energy extraction. The pattern that has been developed allows for independent management of each DC-link voltage in order to track the MPP for each string of PV panels. For various operating circumstances, simulation results are provided.

Power Quality Enhancement of Solar PV Interfaced Distribution System by Delta-Bar-Delta Neural Network

This project presents incremental conductance method for maximum power point tracker (MPPT). Main reason to develop solar photovoltaic energy source is to reduce deterioration in power. Power quality cannot be increases by the week distribution of grid. To increases the power of the grid solar energy conversion system paramount by implementation of a robust control technique. In this project we are we have control algorithm such as delta bar delta but neural network which is in control technique by this active power will be fed to the loads and remaining power to the grid as a function of distribution static compensator it has the capability of mitigating harmonics and balancing of loss and improving power factor. The delta bar delta neural network control algorithm has a capability to adjust weight adaptively in an independent manner and it offers alleviation in the model complexity predominant during an abnormal great conditions along with a reduction in complexion time. This model is efficient utilization accomplished with incremental conductance based on maximum power point tracking techniques for validating the behaviour of proposed system and we can expect this results in the simulation via MATLAB. The realization of MPPT controller can be based on different methods and algorithms. The results and technique include incremental conductance techniques due to the reduced oscillations while determining the Maximum PowerPoint is preferred here and it is also suitable for commercial purpose.

A global power quality index for assessment in distributed energy systems connected to a harmonically polluted network

ABSTRACT Renewable-based generation technologies are gradually making their way into modern delivery grids due to their various advantages, but power quality (PQ) remains a deciding factor for their satisfactory operation. The assessment of overall power quality performance of grid-connected renewable-based distributed energy systems (DESs) is undeniably a complicated process due to their susceptibility to load side and background PQ disturbances, as well as quite a few PQ disturbances produced by the distributed generator (DG) itself. The aim of this article to make the PQ evaluation of the identical rather streamlined by integrating the apprehensive PQ indices at separate bus groups along with the total PQ performances of separate bus groups in one composite index by making use of the analytic hierarchy process (AHP). The technique suggested for formulation yields a centralized global power quality index (GPQI) intended for three categories of bus, namely utility, load, and DG, as well as the overall system. The proposed GPQI is supposed to be exclusively ample to benchmark the global PQ performance of grid-connected DGs with respect to the customized threshold level, in addition to the PQ performance levels grading between the diverse DG systems differentiated by either resource forms or sittings in a large distribution power system. This kind of global index would significantly facilitate the PQ evaluation of grid-integrated DESs. In addition, it may also be extremely useful for distribution network operators (DNOs) to track and penalize DG operators for working inadequately on PQ perspective, and to inspire them to follow the best alternative across numerous power quality improvement (PQI) technologies. The proposed methodology’s applicability is developed and authenticated by applying it in MATLAB on a grid-integrated solar energy conversion system (SECS). The obtained values of GPQIs, by applying the proposed approach in the test system, for the utility, DG, load bus and overall system respectively are 1.530, 1.727, 1.719, and 1.659, respectively, indicating the poor PQ performance of the DG unit under study. The effects of background voltage distortion (BVD) on the utility side and nonlinearity level (NLL) on the load side on the proposed index are also thoroughly investigated. The simulation findings obtained at different NLL and BVD levels affirm the proposed approach’s efficacy in correctly indicating the status of overall PQ in the concerned DG system.

(Invited) Tetracene Molecular Architectures for High-Yield and Long-Lived Individual Triplet States through Singlet Fission

Singlet fission (SF) is a multi-exciton generation process in two neighboring organic chromophores (S1 + S0) where two individual triplet excitons (T1 + T1) are generated from one-photon absorption through a correlated triplet pair (TT). Therefore, SF is highly promising for construction of next-generation solar energy conversion systems such as photovoltaics and photocatalysis. In addition to the close interaction of two nearby molecules, energy-level matching condition between a singlet and two triplet states: [E(S1) ≥ 2E(T1)] are required. Acene derivatives such as pentacene and tetracene satisfy the above condition. However, the number of high-yield and long-lived triplet excited states through SF using tetracene derivatives is extremely limited because of the acceleration of the reverse reaction: triplet-triplet annihilation. Namely, the precise structural control of orientation and distance between two nearby tetracene units is definitely required for long-lived individual triplets through SF. In this presentation, we mainly focus on the tetracene molecular assemblies for high-yield and long-lived individual triplet states through SF using a series of covalently-linked dimers1 and tetracene-modified gold nanoclusters.2 References Nakamura, S.; Sakai, H.; Nagashima, H.; Kobori, Y.; Tkachenko, N. V.; Hasobe, T. ACS Energy Lett. 2019, 4, 26-31.Saegusa, T.; Sakai, H.; Nagashima, H.; Kobori, Y.; Tkachenko, N. V.; Hasobe, T. J. Chem. Soc. 2019, 141, 14720-14727.