Double-Doped Carbon-Based Electrodes with Nitrogen and Oxygen to Boost the Areal Capacity of Zinc-Bromine Flow Batteries

Ensuring a stable power output from renewable energy sources,such as wind and solar energy,depends on the development of large-scale and long-duration energy storage devices.Zinc–bromine fl ow batteries(ZBFBs)have emerged as cost-eff ective and high-energy-density solutions,replacing expensive all-vanadium fl ow batteries.However,uneven Zn deposition during charging results in the formation of problematic Zn dendrites,leading to mass transport polarization and self-discharge.Stable Zn plating and stripping are essential for the successful operation of high-areal-capacity ZBFBs.In this study,we successfully synthesized nitrogen and oxygen co-doped functional carbon felt(NOCF4)electrode through the oxidative polymerization of dopamine,followed by calcination under ambient conditions.The NOCF4 electrode eff ectively facilitates effi cient“shuttle deposition”of Zn during charging,signifi cantly enhancing the areal capacity of the electrode.Remarkably,ZBFBs utilizing NOCF4 as the anode material exhibited stable cycling performance for 40 cycles(approximately 240 h)at an areal capacity of 60 mA h/cm^(2).Even at a high areal capacity of 130 mA h/cm^(2),an impressive energy effi ciency of 76.98%was achieved.These fi ndings provide a promising pathway for the development of high-areal-capacity ZBFBs for advanced energy storage systems.

Development of High Areal Capacity Electrolytic MnO_(2)-Zn Battery via an Iodine Mediator

The commercialization of electrolytic MnO_(2)-Zn batteries is highly applauded owing to the advantages of cost-effectiveness,high safety,high energy density,and durable working performance.However,due to the low reversibility of the cathode MnO_(2)/Mn^(2+)chemistry at high areal capacities and the severe Zn anode corrosion,the practical application of MnO_(2)-Zn batteries is hampered by inadequate lifespan.Leveraging the full advantage of an iodine redox mediator,here we design a highly rechargeable electrolytic MnO_(2)-Zn battery with a high areal capacity.The MnO_(2)-Zn battery coupled with an iodine mediator in a mild electrolyte shows a high discharge voltage of 1.85 V and a robust areal capacity of 10 mAh cm^(-2)under a substantial discharge current density of 160 mA cm^(-2).The MnO_(2)/I_(2)-Zn battery with an areal capacity of 10 mAh cm^(-2)exhibits prolonged stability of over 950 cycles under a high-capacity retention of~94%.The scaled-up MnO_(2)/I_(2)-Zn battery reveals a stable cycle life under a cell capacity of~600 mAh.Moreover,our constructed MnO_(2)/I_(2)-Zn battery demonstrates a practical energy density of~37 Wh kg^(-1)and a competitive energy cost of<18 US$kWh^(-1)by taking into account the cathode,anode,and electrolyte.The MnO_(2)/I_(2)-Zn battery,with its remarkable reversibility and reasonable energy density,enlightens a new arena of large-scale energy storage devices.

Enlarging Zn deposition space via regulating Sn-induced effective interface for high areal capacity zinc-based flow battery

Zinc-based flow batteries(ZFBs)have aroused great favor in large-scale energy storage due to the high security and low cost.However,the low areal capacity arising from the limited space for Zn plating hinders the further development.Herein,a novel carbon felt-Sn-carbon felt sandwich host(CSCH)is designed and constructed.Benefiting from the strong chemical absorption and the dehydration effect on Zn(H_(2)O)_(6)^(2+),the Sn activation layer in the CSCH demonstrates the lowest comprehensive resistance for Zn deposition.Thus,Zn is induced to nucleate preferentially on the Sn activation layer,and grows towards the membrane,regulating the spatial distribution of Zn electrochemical deposits,which remarkably improves the areal capacity and cyclic stability of Zn anode.Consequently,the zinc-bromine flow batteries equipped with CSCH electrodes can achieve the ultra-high areal capacity of 120 mA h cm^(-2)at 80 mA cm^(-2),and run stably for 140 h with average energy efficiency of 80.3%in the extreme condition(80 mA cm^(-2),80 mA h cm^(-2)).This innovative work will inspire future advanced designs for high areal capacity electrodes in ZFBs.

研磨表面微观形貌的三维检测及Areal表征

介绍了三维表面微观形貌的检测方法,分析了采用高斯滤波提取基准中面的原理,针对研磨表面形貌的表征选取了一组Areal表征参数。运用原子力显微镜(AFM)扫描研磨工件的表面,采用高斯滤波提取基准中面进而分离出表面微观形貌的三维信息,在此基础上计算出表征参数值。试验表明研磨表面微观形貌呈现高斯分布规律,采用高斯滤波方法及所选的Areal表征参数能够有效地表征研磨表面的三维微观形貌。

面向功能的表面形貌Areal表征与评定

表面功能特性的实现受表面形貌直接的影响,表面形貌的二维表征已不能满足当前工程界的需要,表面评定体系由二维转向三维是一种必然趋势.Areal表征是由二维轮廓法延伸出来的三维面域表征.分析了主要的Areal表征参数,联系表面的功能特性要求,确立了表征参数的选取顺序及其与表面功能的对应表征关系,针对不同表面功能要求而选择不同表征参数进行评定,解决了零件表面功能复杂与评定参数众多且选择困难的矛盾.

分形表面三维形貌Areal参数表征研究

以WM分形函数模拟机械加工表面,采用最小二乘平面作为基准平面,对三维表面形貌Areal表征参数(14+3)体系进行全面分析,包括幅度参数、空间参数、综合参数、功能参数等4类形貌参数,并分析三维表面分形维数与表面形貌表征参数的相关关系,以此探究表面形貌参数对表面功能的影响。研究结果表明:三维WM分形表面近似于高斯表面,服从高斯分布;WM分形表面的分形维数与三维表面形貌参数之间存在一定关系,幅度参数和综合参数与分形维数呈现标准的线性分布,这2类参数与表面功能存在密切关系;而空间参数和功能参数随分形维数的增大变化不大,对表面功能的影响并不明显。

Towards full demonstration of high areal loading sulfur cathode in lithium–sulfur batteries

Lithium–sulfur(Li–S)batteries have been recognized as promising substitutes for current energy-storage technologies owing to their exceptional advantages in very high-energy density and excellent material sustainability.The cathode with high sulfur areal loading is vital for the practical applications of Li–S batteries with very high energy density.However,the high sulfur loading in an electrode results in poor rate and cycling performances of batteries in most cases.Herein,we used diameters of 5.0(D5)and 13.0(D13)mm to probe the effect of electrodes with different sizes on the rate and cycling performances under a high sulfur loading(4.5 mg cm^-2).The cell with D5 sulfur cathode exhibits better rate and cycling performances comparing with a large(D13)cathode.Both the high concentration of lithium polysulfides and corrosion of lithium metal anode impede rapid kinetics of sulfur redox reactions,which results in inferior battery performance of the Li–S cell with large diameter cathode.This work highlights the importance of rational matching of the large sulfur cathode with a high areal sulfur loading,carbon modified separators,organic electrolyte,and Li metal anode in a pouch cell,wherein the sulfur redox kinetics and lithium metal protection should be carefully considered under the flooded lithium polysulfide conditions in a working Li–S battery.

Seismological method for prediction of areal rockbursts in deep mine with seismic source mechanism and unstable failure theory

The research on the rock burst prediction was made on the basis of seismology,rock mechanics and the data from Dongguashan Copper Mine(DCM) ,the deepest metal mine in China.The seismic responses to mining in DCM were investigated through the analyses of the spatio-temporal distribution of hypocenters,apparent stress and displacement of seismic events,and the process of the generation of hazardous seismicity in DCM was studied in the framework of the theory of asperity in the seismic source mechanism.A method of locating areas with hazardous seismicity and a conceptual model of hazardous seismic nucleation in DCM were proposed.A criterion of rockburst prediction was analyzed theoretically in the framework of unstable failure theories,and consequently,the rate of change in the ratio of the seismic stiffness of rock in a seismic nucleation area to that in surrounding area,dS/dt,is defined as an index of the rockburst prediction.The possibility of a rockburst will increase if dS/dt>0,and the possibility of rock burst will decrease if dS/dt<0.The correctness of these methods is demonstrated by analyses of rock failure cases in DCM.

3D N,O-Codoped Egg-Box-Like Carbons with Tuned Channels for High Areal Capacitance Supercapacitors

Functional carbonaceous materials for supercapacitors(SCs)without using acid for post-treatment remain a substantial challenge.In this paper,we present a less harmful strategy for preparing three-dimensional(3D)N,O-codoped egg-box-like carbons(EBCs).The as-prepared EBCs with opened pores provide plentiful channels for ion fast transport,ensure the e ective contact of EBCs electrodes and electrolytes,and enhance the electron conduction.The nitrogen and oxygen atoms doped in EBCs improve the surface wettability of EBC electrodes and provide the pseudocapacitance.Consequently,the EBCs display a prominent areal capacitance of 39.8μF cm-2(340 F g-1)at 0.106 m A cm-2 in 6 M KOH electrolyte.The EBC-based symmetric SC manifests a high areal capacitance to 27.6μF cm-2(236 F g-1)at 0.1075 m A cm-2,a good rate capability of 18.8μF cm-2(160 F g-1)at 215 m A cm-2 and a long-term cycle stability with only 1.9%decay after 50,000 cycles in aqueous electrolyte.Impressively,even in all-solid-state SC,EBC electrode shows a high areal capacitance of 25.0μF cm-2(214 F g-1)and energy density of 0.0233 m Wh cm-2.This work provides an acid-free process to prepare electrode materials from industrial by-products for advanced energy storage devices.

The role of functional materials to produce high areal capacity lithium sulfur battery

The lithium sulfur batteries(LSBs) are considered as one of the promising next generation energy storage devices due to the high theoretical specific capacity of sulfur(1675 m Ah g-1), naturally available, low cost.However, the practical LSBs are impeded by the well-known "shuttle effect" combined with other technical drawbacks. The "shuttle effect" causes rapid capacity decay, severe self-discharging and low active material utilization. The polysulfide(PS) which has lone pair electrons in each sulfur atom is considered as Lewis base and shows strong affinity to various polar, Lewis acid and catenation interactive materials but very weakly interacts with the non-polar conductive carbons. The "shuttle effect" occurs due to the diffusion of high order PS from the cathode to the anode and then low-order PS back to the cathode. The PS is polar and, due to a lone pair of electrons associated with the sulfur atom, is considered a Lewis base. As such, the PS shows a strong affinity with various polar and Lewis acid materials. In addition, a more novel trapping can be performance through a catenation reaction. For LSBs to compete with the state-of-the-art lithium ion batteries(LIBs), the LSB areal capacity need to be ~6 m Ah cm-2(which is proportional to sulfur loading). To achieve this target the PS shuttling needs to mitigate, which can be achieved through using functional materials. This review addresses the aforementioned phenomena by considering the PS phase interacts with the various functional materials and how this impacts areal capacity and cycling stability of LSBs.

A Silicon Monoxide Lithium-Ion Battery Anode with Ultrahigh Areal Capacity

Silicon monoxide(SiO)is an attractive anode material for next-generation lithium-ion batteries for its ultra-high theoretical capacity of 2680 mAh g−1.The studies to date have been limited to electrodes with a rela-tively low mass loading(<3.5 mg cm^(−2)),which has seriously restricted the areal capacity and its potential in practical devices.Maximizing areal capacity with such high-capacity materials is critical for capitalizing their potential in practi-cal technologies.Herein,we report a monolithic three-dimensional(3D)large-sheet holey gra-phene framework/SiO(LHGF/SiO)composite for high-mass-loading electrode.By specifically using large-sheet holey graphene building blocks,we construct LHGF with super-elasticity and exceptional mechanical robustness,which is essential for accommodating the large volume change of SiO and ensuring the structure integrity even at ultrahigh mass loading.Additionally,the 3D porous graphene network structure in LHGF ensures excellent electron and ion transport.By systematically tailoring microstructure design,we show the LHGF/SiO anode with a mass loading of 44 mg cm^(−2)delivers a high areal capacity of 35.4 mAh cm^(−2)at a current of 8.8 mA cm^(−2)and retains a capacity of 10.6 mAh cm^(−2)at 17.6 mA cm^(−2),greatly exceeding those of the state-of-the-art commercial or research devices.Furthermore,we show an LHGF/SiO anode with an ultra-high mass loading of 94 mg cm^(−2)delivers an unprecedented areal capacity up to 140.8 mAh cm^(−2).The achievement of such high areal capacities marks a critical step toward realizing the full potential of high-capacity alloy-type electrode materials in practical lithium-ion batteries.

Viscous fingering and its effect on areal sweep efficiency during waterflooding: an experimental study

Viscous fingering is one of the main challenges that could reduce areal sweep efficiency during waterflooding in oil reservoirs. A series of waterflooding experiments were carried out in a Hele-Shaw cell at ambient temperature during which areal sweep efficiency was estimated and techniques to ease the fingering problem were examined. The onset and propagation of viscous fingers were monitored as a function of both injection rate and injection/production positions. Image processing techniques were utilized to quantitatively investigate the propagation of fingers. The experimental results show that, under specific conditions, increasing the number of finger branches could improve the areal sweep efficiency, whereas growth of a single narrow finger has a negative impact on oil displacement efficiency. According to the obtained results,increasing the injection rate improves the areal sweep efficiency up to a critical rate at which viscous fingers start to grow.The impact of heterogeneity of the medium on distributing the viscous fingers was also investigated by introducing two different arrangements of fractures in the model. The results show that fractures perpendicular to the direction of flow would distribute the displacing water more uniformly, while fractures in the direction of flow would amplify the unfavorable sweep efficiency.

Areal density and spatial resolution of high energy electron radiography

Ultrafast imaging tools are of great importance for determining the dynamic density distribution in high energy density(HED)matter.In this work,we designed a high energy electron radiography(HEER)system based on a linear electron accelerator to evaluate its capability for imaging HED matter.40 MeV electron beams were used to image an aluminum target to study the density resolution and spatial resolution of HEER.The results demonstrate a spatial resolution of tens of micrometers.The interaction of the beams with the target and the beam transport of the transmitted electrons are further simulated with EGS5 and PARMELA codes,with the results showing good agreement with the experimental resolution.Furthermore,the experiment can be improved by adding an aperture at the Fourier plane.

A novel one-step reaction sodium-sulfur battery with high areal sulfur loading on hierarchical porous carbon fiber

Room temperature sodium-sulfur(RT Na-S)batteries are gaining extensive attention as attractive alternatives for large-scale energy storage,due to low cost and high abundancy of sodium and sulfur in nature.However,the dilemmas regarding soluble polysulfides(Na_(2)Sn,4<n<8)and the inferior reaction kinetics limit their practical application.To address these issues,we report the activated porous carbon fibers(APCF)with small sulfur molecules(S2-4)confined in ultramicropores,to achieve a reversible single-step reaction in RT Na-S batteries.The mechanism is investigated by the in situ UV/vis spectroscopy,which demonstrates Na2S is the only product during the whole discharge process.Moreover,the hierarchical carbon structure can enhance areal sulfur loading without sacrificing the capacity due to thorough contact between electrolyte and sulfur electrode.As a consequence,the APCF electrode with 38 wt%sulfur(APCF-38S)delivers a high initial reversible specific capacity of 1412 mAh g^(-1) and 10.6mAh cm^(-2)(avg.areal sulfur loading:7.5 mg cm^(-2))at 0.1 C(1C=1675 mA g^(-1)),revealing high degree of sulfur utilization.This study provides a new strategy for the development of high areal capacity RT Na-S batteries.

Nitrogen and fluorine co-doped TiO_(2)/carbon microspheres for advanced anodes in sodium-ion batteries: High volumetric capacity, superior power density and large areal capacity

Fast charging and high volumetric capacity are two of the critical demands for sodium-ion batteries(SIBs).Although nanostructured materials achieve outstanding rate performance,they suffer from low tap density and small volumetric capacity.Therefore,how to realize large volumetric capacity and high tap density simultaneously is very challenging.Here,N/F co-doped TiO_(2)/carbon microspheres(NF- TiO_(2)/C)are synthesized to achieve both of them.Theoretical calculations reveal that N and F co-doping increases the contents of oxygen vacancies and narrows the bandgaps of TiO_(2) and C,improving the electronic conductivity of NF- TiO_(2)/C.Furthermore,NF- TiO_(2)/C exhibits the high binding energy and low diffusion energy barrier of Na+,significantly facilitating Na+storage and Na+diffusion.Therefore,NF- TiO_(2)/C offers a high tap density(1.51 g cm^(-3)),an outstanding rate performance(125.9 mAh g^(-1) at 100 C),a large volumetric capacity(190 mAh cm^(-3) at 100 C),a high areal capacity(4.8 mAh cm^(-2))and an ultra-long cycling performance(80.2%after 10,000 cycles at 10 C)simultaneously.In addition,NF- TiO_(2)/C||Na_(3)V_(2)(PO_(4))_(3) full cells achieve an ultrahigh power density of 25.2 kW kg^(-1).These results indicate the great promise of NF- TiO_(2)/C as a high-volumetric-capacity and high-power-density anode material of SIBs.

DD proton spectrum for diagnosing the areal density of imploded capsules on Shenguang Ⅲ prototype laser facility

The primary DD proton spectrum is used for diagnosing the fuel-shell areal density pR of imploded capsules on Shenguang Ⅲ （SG-Ⅲ） prototype laser facility for the first time. A charged particle spectrometer （CPS） with a CR39 nuclear track detector is used to measure the DD proton spectrum. The proton spectrum is determined from both the proton track and its size. A typical proton energy peak shift from 3.02 MeV to 2.6 MeV is observed in our experiment, which yields a maximum pR larger than 6 mg/cm2.

“All‐In‐One” integrated ultrathin SnS2@3D multichannel carbon matrix power high‐areal–capacity lithium battery anode

Construction of a thickness‐independent electrode with high active material mass loading is crucial for the development of high energy rechargeable lithium battery.Herein,we fabricate an all‐in‐one integrated SnS2@3D multichannel carbon matrix(SnS2@3DMCM)electrode with in‐situ growth of ultrathin SnS2 nanosheets inside the inner walls of three dimensional(3D)multichannels.The interconnected conductive carbon matrix derived from natural wood acts as an integrated porous current collector to avail the electrons transport and accommodate massive SnS2 nanosheets,while plenty of 3D aligned multichannels facilitate fast ions transport with electrode thickness‐independent even under high mass loading.As expected,the integrated SnS2@3DMCM electrode exhibits remarkable electrochemical lithium storage performance,such as exceptional high‐areal‐capacity of 6.4 mAh cm−2,high rate capability of 3 mAh cm−2 under current of 6.8 mAcm−2(10 C),and stable cycling performance of 6.8 mAcm−2 with a high mass loading of 7mg cm−2.The 3D integrated porous electrode constructing conveniently with the natural source paves new avenues towards future high‐performance lithium batteries.

Mesh-like vertical structures enable both high areal capacity and excellent rate capability

In order to balance electrochemical kinetics with loading level for achieving efficient energy storage with high areal capacity and good rate capability simultaneously for wearable electronics,herein,2 D meshlike vertical structures(NiCo_2 S_4@Ni(OH)_2) with a high mass loading of 2.17 mg cm^(-2) and combined merits of both 1 D nanowires and 2 D nanosheets are designed for fabricating flexible hybrid supercapacitors.Particularly,the seamlessly interconnected NiCo_2 S_4 core not only provides high capacity of 287.5 μAh cm^(-2) but also functions as conductive skeleton for fast electron transport;Ni(OH)_2 sheath occupying the voids in NiCo_2 S_4 meshes contributes extra capacity of 248.4 μAh cm^(-2);the holey features guarantee rapid ion diffusion along and across NiCO_2 S_4@Ni(OH)_2 meshes.The resultant flexible electrode exhibits a high areal capacity of 535.9 μAh cm^(-2)(246.9 mAh g^(-1)) at 3 mA cm^(-2) and outstanding rate performance with 84.7% retention at 30 mA cm^(-2),suggesting efficient utilization of both NiCo_2 S_4 and Ni(OH)_2 with specific capacities approaching to their theoretical values.The flexible solid-state hybrid device based on NiCo_2 S_4@Ni(OH)_2 cathode and Fe_2 O_3 anode delivers a high energy density of 315 μWh cm^(-2) at the power density of 2.14 mW cm^(-2) with excellent electrochemical cycling stability.

Areal differentiation of virtual water for agricultural products and its effect on regional agricultural structure adjustment in China: 1995-2007

With a vast territory, the space-time distribution of water resources is uneven in China. There is a great dif ference in natural conditions and farmland management of agricuttural production in different regions. The areal differentiation of agricultural products virtual water is obvious. Comparison with the agricultural products virtual water from 1995 to 2007 in China shows an increase in the first ten vears and a little decrease in recent years. There has been a tendency of increase all the time in Northeast and Northwest. but a decrease after an increase firstly in other regions. The virtual water offood crops is the maximum which accounts for more than 70% in China. and that of vegetables is in a fast growth. The proportion of agricultural products virtual water to the total water resources in each region has a large difference, showing the imbalance of agricultural water in different regions, which accounts for 50%-90% in Northeast, and 125%-185% in North China. Under the guidance of virtual water strategy, based on the differences of resource endowment, each region should adjust agricultural structure, decide production by water, and select water suitable crops. In water-rich region, agricultural produets of high water consumption should be planted appropriately, which will make full use of the abundant local water resources. In water-shortage region the crop production of high water consumption and low efficiency should be depressed, and that of low water consumption and high efficiency should be supported and increased. It will achieve reasonable disposition of water resources, promote ecological restoration and environmental protection, as welt as ensure food security.

AREAL DIFFERENTIATION AND CONSTRUCTION OF OASIS AGRICULTURAL ECOSYSTEM IN THE SHIYANG RIVER BASIN

On the basis of the study on areal differentiation of the natural environment of oasis agriculture ecosystems in the Shiyang River Basin, this paper comparatively analyzes the natural productivities, water economic benefits, production efficiency, ecological stabilities and developmental conditions of the Wuwei Oasis agricultural ecosystem in the middle reaches of the river basin and the Minqin Oasis agricultural ecosystem in the lower reaches. Under a same management level and investment of . material and energy, primary productiveness and economic benefits of the former are higher than those of the latter. Construction directions of Wuwei and Minqin oases should be different in order to alleviate the water- use contradiction between the middle and lower reaches. The construction objective of Wuwei Oasis should be efficient irrigated farming production system and Minqin Oasis should become a mixed forestry-pastoral-farming ecosystem taking ecological protection as its major function.