Li–CO2 and Na–CO2 Batteries: Toward Greener and Sustainable Electrical Energy Storage

Metal–CO₂ batteries, especially Li–CO₂ and Na–CO₂ batteries, offer a novel and attractive strategy for CO₂ capture as well as energy conversion and storage with high specific energy densities. However, some scientific issues and challenges existing restrict their practical applications. Here, recent progress of crucial reaction mechanisms on cathodes in Li–CO₂ and Na–CO₂ batteries are summarized. The detailed reaction pathways can be modified by operation conditions, electrolyte compositions, and catalysts. Besides, specific discussions from aspects of catalyst design, stability of electrolytes, and anode protection are presented. Perspectives of several innovative directions are also put forward. This review provides an intensive understanding of Li–CO₂ and Na–CO₂ batteries and gives a useful guideline for the practical development of metal–CO₂ batteries and even metal–air batteries.     

Observed Effects of Vibrationally Induced Fretting on Bearing–Shaft Systems in Flywheel Energy Storage Systems

Mechanical bearings in a flywheel energy storage system (FESS) may experience unique wear patterns due to the vacuum condition that such systems operate under. The FESS discussed herein uses an aluminum flywheel rotor hub with an integrated shaft and full silicon nitride ceramic bearings. The bearings experienced fretting wear, as is common to many bearing–shaft systems, which eroded the naturally forming oxide layer on the surface of the shaft which was not replaced due to the lack of oxygen. This exposed the soft aluminum surface below creating the opportunity for material transfer between the surfaces and cold welding between components to occur. The existence of fretting and material transfer is demonstrated, and the opportunity for cold welding between components is discussed. The effects of these processes on system components are described. Recommendations to avoid or mitigate fretting and adhesion damage to the system are made for the studied FESS in particular, and, more generally, similar systems operating in vacuum conditions.     

Natural Cocoons Enabling Flexible and Stable Fabric Lithium–Sulfur Full Batteries

Lithium–sulfur batteries are highly appealing as highenergy power systems and hold great application prospects for flexible and wearable electronics.However,the easy formation of lithium dendrites,shuttle effect of dissolved polysulfides,random deposition of insulating lithium sulfides,and poor mechanical flexibility of both electrodes seriously restrict the utilization of lithium and stabilities of lithium and sulfur for practical applications.Herein,we present a cooperative strategy employing silk fibroin/sericin to stabilize flexible lithium–sulfur full batteries by simultaneously inhibiting lithium dendrites,adsorbing liquid polysulfides,and anchoring solid lithium sulfides.Benefiting from the abundant nitrogen-and oxygen-containing functional groups,the carbonized fibroin fabric serves as a lithiophilic fabric host for stabilizing the lithium anode,while the carbonized fibroin fabric and the extracted sericin are used as sulfiphilic hosts and adhesive binders,respectively,for stabilizing the sulfur cathode.Consequently,the assembled Li–S full battery provided a high areal capacity(5.6 mAh cm?2),limited lithium excess(90%),a high volumetric energy density(457.2 Wh L^?1),high-capacity retention(99.8%per cycle),and remarkable bending capability(6000 flexing cycles at a small radius of 5 mm).     

An Iron-Decorated Carbon Aerogel for Rechargeable Flow and Flexible Zn–Air Batteries

Mechanically stable and foldable air cathodes with exceptional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activities are key components of wearable metal–air batteries. Herein, a directional freeze-casting and annealing approach is reported for the construction of a 3D honeycomb nanostructured, N,P-doped carbon aerogel incorporating in situ grown FeP/Fe₂O₃ nanoparticles as the cathode in a flexible Zn–air battery (ZAB). The aqueous rechargeable Zn–air batteries assembled with this carbon aerogel exhibit a remarkable specific capacity of 648 mAh g⁻¹ at a current density of 20 mA cm⁻² with a good long-term durability, outperforming those assembled with commercial Pt/C+RuO₂ catalyst. Furthermore, such a foldable carbon aerogel with directional channels can serve as a freestanding air cathode for flexible solid-state Zn–air batteries without the use of carbon paper/cloth and additives, giving a specific capacity of 676 mAh g⁻¹ and an energy density of 517 Wh kg⁻¹ at 5 mA cm⁻² together with good cycling stability. This work offers a new strategy to design and synthesize highly effective bifunctional air cathodes to be applied in electrochemical energy devices.     

Decoupled Solar Energy Storage and Dark Photocatalysis in a 3D Metal–Organic Framework

Materials enabling solar energy conversion and long-term storage for readily available electrical and chemical energy are key for off-grid energy distribution. Herein, the specific confinement of a rhenium coordination complex in a metal–organic framework (MOF) unlocks a unique electron accumulating property under visible-light irradiation. About 15 C g_MOF⁻¹ of electric charges can be concentrated and stored for over four weeks without loss. Decoupled, on-demand discharge for electrochemical reactions and H₂ evolution catalysis is shown and light-driven recharging can be conducted for >10 cycles with ≈90% of the initial charging capacity retained. Experimental investigations and theoretical calculations link electron trapping to MOF-induced geometry constraints as well as the coordination environment of the Re-center, highlighting the key role of MOF confinement on molecular guests. This study serves as the seminal report on 3D porous colloids achieving photoaccumulation of long-lived electrons, unlocking dark photocatalysis, and a path toward solar capacitor and solar battery systems.     

Synthesis and Hydrogen Storage in Single—walled Carbon Nanotubes

Single=walled carbon nanotubes(SWNTs) were synthesized by a hydrogen arc discharge method.A high yield of gram quantity of SWNTs per hour was achieved.Tow kinds of SWNT products:web-like substancea and thin films in large slices were obtained. Results of resonant Raman scattering measurements indicate that the SWNTs prepared have a wider diameter distribution and a larger mean diameter.Hydrogen uptake measurements of the two kinds of SWNT samples(both as prepared and pretreated) were carried out using a high pressure volumetric method,respectively.And a hydrogen storage capacity of 4 wt pct could be repeatedly achieved for the suitably pretreated SWMNTs,whicb indicates that SWNTs may be a promising hydrogen storge material.     

Biomass-Derived Bifunctional Cathode Electrocatalyst and Multiadaptive Gel Electrolyte for High-Performance Flexible Zn–Air Batteries in Wide Temperature Range

High-efficiency and low-cost bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), as well as gel electrolytes with high thermal and mechanical adaptability are required for the development of flexible batteries. Herein, abundant Setaria Viridis (SV) biomass is selected as the precursor to prepare porous N-doped carbon tubes with high specific surface area and the 900 °C calcination product of SV (SV-900) shows the optimum ORR/OER activities with a small E_OER–E_ORR of 0.734 V. Meanwhile, a new multifunctional gel electrolyte named C20E2G5 is prepared using cellulose extracted from another widely distributed biomass named flax as the skeleton, epichlorohydrin as the cross-linker and glycerol as the antifreezing agent. C20E2G5 possesses high ionic conductivity from −40 to + 60 °C, excellent tensile and compressive resistance, high adhesion, strong freezing and heat resistance. Moreover, the symmetrical cell assembled with C20E2G5 can significantly inhibit Zn dendrite growth. Finally, flexible solid-state Zn–air batteries assembled with SV-900 and C20E2G5 show high open circuit voltage, large energy density, and long-term operation stability between −40 and + 60 °C. This biomass-based approach is generic and can be used for the development of diverse next-generation electrochemical energy conversion and storage devices.     

Oxygen?Defect Enhanced Anion Adsorption Energy Toward Super?Rate and Durable Cathode for Ni–Zn Batteries

The alkaline zinc-based batteries with high energy density are becoming a research hotspot. However, the poor cycle stability and low-rate performance limit the...     

Nuclear Energy—the Strategic Role and Sustainability in China

analyzing the challenges of China’s energy supply, an excellent perspective of nuclear power development in china has been described. Taking into account the midlong term development requirements, a comprehensive, coordinated and sustainable nuclear power strategic consideration and proposal is put forward. Thus our national nuclear industry can not only catch up with the world advanced level in proper time, but also possess the enough stamina of sustainability.     

High-Performance Biodegradable Energy Storage Devices Enabled by Heterostructured MoO3–MoS2 Composites

Biodegradable implantable devices are of growing interest in biosensors and bioelectronics. One of the key unresolved challenges is the availability of power supply. To enable biodegradable energy-storage devices, herein, 2D heterostructured MoO₃–MoS₂ nanosheet arrays are synthesized on water-soluble Mo foil, showing a high areal capacitance of 164.38 mF cm⁻² (at 0.5 mA cm⁻²). Employing the MoO₃–MoS₂ composite as electrodes of a symmetric supercapacitor, an asymmetric Zn-ion hybrid supercapacitor, and an Mg primary battery are demonstrated. Benefiting from the advantages of MoO₃–MoS₂ heterostructure, the Zn-ion hybrid supercapacitors deliver a high areal capacitance (181.86 mF cm⁻² at 0.5 mA cm⁻²) and energy density (30.56 µWh cm⁻²), and the Mg primary batteries provide a stable high output voltage (≈1.6 V) and a long working life in air/liquid environment. All of the used materials exhibit desirable biocompatibility, and these fabricated devices are also fully biodegradable. Demonstration experiments display their potential applications as biodegradable power sources for various electronic devices.     

Low-Cost Titanium–Bromine Flow Battery with Ultrahigh Cycle Stability for Grid-Scale Energy Storage

Flow batteries are one of the most promising large-scale energy-storage systems. However, the currently used flow batteries have low operation–cost-effectiveness and exhibit low energy density, which limits their commercialization. Herein, a titanium–bromine flow battery (TBFB) featuring very low operation cost and outstanding stability is reported. In this battery, a novel complexing agent, 3-chloro-2-hydroxypropyltrimethyl ammonium chloride, is employed to stabilize bromine/polybromides and suppress Br diffusion. The results reveal that the complexing agent effectively inhibits Br crossover and reduces Br-induced corrosivity, which in turn significantly improves the reliability of the TBFB system. The novel TBFB demonstrates 95% coulombic efficiency and 83% energy efficiency at 40 mA cm⁻² current density. Moreover, it can run smoothly for more than 1000 cycles without any capacity decay. Furthermore, an assembled 300 W TBFB stack can be continuously operated for more than 500 cycles, thereby confirming the practical applicability of the proposed TBFB. Because the TBFB utilizes an ultralow-cost electrolyte (41.29 $ kWh⁻¹) and porous polyolefin membranes, it serves as a reliable and low-cost energy-storage device. Therefore, considering its ultrahigh stability and low cost, the TBFB can be used as a large-scale energy-storage device.     

Boosted Storage Kinetics in Thick Hierarchical Micro–Nano Carbon Architectures for High Areal Capacity Li-Ion Batteries

A practical and effective approach to increase the energy storage capacity of lithium ion batteries(LIBs) is to boost their areal capacity. Developing thick electrodes is one of the most crucial ways to achieve high areal capacity but limited by sluggish ion/electron transport, poor mechanical stability, and high-cost manufacturing strategies. Here we address these constraints by engineering a unique hierarchical-networked 10 mm thick all-carbon electrode, providing a scalable strategy to produc...     

The Structural and Electronic Engineering of Molybdenum Disulfide Nanosheets as Carbon-Free Sulfur Hosts for Boosting Energy Density and Cycling Life of Lithium–Sulfur Batteries

The compact sulfur cathodes with high sulfur content and high sulfur loading are crucial to promise high energy density of lithium–sulfur (Li–S) batteries. However, some daunting problems, such as low sulfur utilization efficiency, serious polysulfides shuttling, and poor rate performance, are usually accompanied during practical deployment. The sulfur hosts play key roles. Herein, the carbon-free sulfur host composed of vanadium-doped molybdenum disulfide (VMS) nanosheets is reported. Benefiting from the basal plane activation of molybdenum disulfide and structural advantage of VMS, high stacking density of sulfur cathode is allowed for high areal and volumetric capacities of the electrodes together with the effective suppression of polysulfides shuttling and the expedited redox kinetics of sulfur species during cycling. The resultant electrode with high sulfur content of 89 wt.% and high sulfur loading of 7.2 mg cm⁻² achieves high gravimetric capacity of 900.9 mAh g⁻¹, the areal capacity of 6.48 mAh cm⁻², and volumetric capacity of 940 mAh cm⁻³ at 0.5 C. The electrochemical performance can rival with the state-of-the-art those in the reported Li–S batteries. This work provides methodology guidance for the development of the cathode materials to achieve high-energy-density and long-life Li–S batteries.     

Synthesis and Characterization of Mesoporous Titania Particles and Thin Films

Well-organized mesoporous titania particles and thin films were successfully synthesized by using tetrabutyl titanate as the inorganic precursor and triblock copolymer （Pluronic P123） as the template via evaporationinduced self-assembly process. The resulting materials were characterized by high resolution transmission electron microscopy （HRTEM）, X-ray diffraction （XRD）. Fourier-transform infrared spectroscopy （FT-IR）,Brunauer-Emmett-Teller （BET） and atomic force microscopy （AFM）. Macro shape of mesoporous titania would greatly influence the mesostructure of materials, and the probable reasons were also discussed.     

Special Issue— Computer Aided Optimal Design: Structural and Mechanical Systems

A decomposition technique is suggested for optimal design of water supply networks. The general mathematical model is decomposed into two submodels which are solved iteratively. The flow variables are solved in the first submodel for a fixed value of the head variables, using a minimum concave cost flow algorithm. The head variables are solved in the second submodel for a fixed value of the flow variable using LP. The solution is usually obtained after 2 iterations, and is proven to be a local optimum. A novel form of the pump equation, based on dimensional analysis, is also presented and used as part of the optimization model.     

Electrical and Optical Properties of GaSe Thin Films

The structure, electrical transport, and optical properties of GaSe films fabricated by means of radio-frequency (RF) magnetron sputtering in Ar were investigated. The as-sputtered GaSe films were amorphous, and their optical energy gap Eg are 1.9～2.6 eV. The effect of the synthesis conditions on the optical and electrical properties of the GaSe films has also been studied     

Binding S0.6Se0.4 in 1D Carbon Nanofiber with C?S Bonding for High‐Performance Flexible Li–S Batteries and Na–S Batteries

A one‐step synthesis procedure is developed to prepare flexible S_0.6Se_0.4@carbon nanofibers (CNFs) electrode by coheating S_0.6Se_0.4 powder with electrospun polyacrylonitrile nanofiber papers at 600 °C. The obtained S_0.6Se_0.4@CNFs film can be used as cathode material for high‐performance Li–S batteries and room temperature (RT) Na–S batteries directly. The superior lithium/sodium storage performance derives from its rational structure design, such as the chemical bonding between Se and S, the chemical bonding between S_0.6Se_0.4 and CNFs matrix, and the 3D CNFs network. This easy one‐step synthesis procedure provides a feasible route to prepare electrode materials for high‐performance Li–S and RT Na–S batteries.     

Sulfide-Based All-Solid-State Lithium–Sulfur Batteries:Challenges and Perspectives

Lithium–sulfur batteries with liquid electrolytes have been obstructed by severe shuttle effects and intrinsic safety concerns.Introducing inorganic solid-state electrolytes into lithium–sulfur systems is believed as an effective approach to eliminate these issues without sacrificing the high-energy density,which determines sulfidebased all-solid-state lithium–sulfur batteries.However,the lack of design principles for high-performance composite sulfur cathodes limits their further application.Th...     

Energy from thorium—An Indian perspective

Nuclear energy as a sustainable resource in India has been very clearly formulated in the three stage nuclear programme. The role of thorium as a potential fuel in the third stage of this programme has also been elucidated. With this aim there have been pioneering research efforts in all aspects of the thorium fuel cycle. Thorium being fertile and not accompanied by the fissile species requires the use of a fissile topping. There have been several studies in India on the use of thorium in different reactor systems from thermal to intermediate and fast spectrum, molten salt reactors, high temperature reactors, compact nuclear power packs and even Subcritical systems. In this paper, we present some of the research studies on use of thorium in thermal reactor systems. We give an overview of the neutronic properties of thorium and the bred fissile material and then proceed to show the performance potential in different reactor systems. We also present the innovative Indian reactor designs which utilize thorium, namely the Advanced Heavy Water Reactor (AHWR) and the Indian High Temperature Reactors.     

Quantitative Social Research — Belief Systems,the Way of Thinking and Sentiments of Five Nations —

The fundamental ideas of comparative quantitative social research from the international perspectives are mentioned in Introduction. Then a new method called cultural link analysis (abbreviated as CLA) is explained in section 2.

CLA includes the following three subjects.

• a. A spatial link inherent in the selection of the subject culture or society

• b. An item-structure link inherent in the commonalities and differences in item response patterns within and across different cultures

• c. A temporal link inherent in longitudinal analysis.

The design of data, based on this CLA, i.e. the method of cross-societal five nations’ surveys is described in the next section 3.

In the following sections, the analysis of data based on CLA are discussed. These topics are divided into two parts. In the first part, the formation of spatial link is depicted depending on the questions taken up in section 3. First, it emerges that Japanese-Americans in Hawaii make a linkage between Japanese and Americans. Then, it is shown that various links among the peoples in different cultures are found, depending on the questions used for analysis.

Section 4 (I) Japanese Americans in Hawaii as a linkage between Japanese and Americans

• (a) An Aesop’s fable

• (b) Interpersonal relations

• (c) Intermediate answers

Section 4(II) Relational graphic representation of each population based on simple tabulation. How chains are found …1.

Section 4(III) Relational graphic representation of each population based on the way of thinking and belief systems. How chains are found… 2.

In the second part, the results of analysis for the peoples in different cultures are discussed, based on the idea of “link of questions” in section 5.

Section 5(I) Analysis of various sets of questions

• (a) Trustfulness and work

• (b) Money, work and national goals

• (c) Aesop’s fable and related social attitudes

Section 5(II) Analysis on various scales

• (a) Analysis in every nation

• (b) Analysis by nation and concept-scale

• (c) Analysis by nation, scales and other questions

Section 6 Concluding remarks

The discussions of temporal link are not described here because, this problem has been already discussed in details in the book of “DAIGO NIHONJIN NO KOKUMINSEI” (The Fifth Volume of Japanese National Character), by Research Committee of Japanese National Character, The Institute of Statistical Mathematics; IDEMITSU SHOTEN, April, 1992.