Carbon foam with microporous structure for high performance symmetric potassium dual-ion capacitor

A novel carbon foam with microporous structure(CFMS),with the advantages of a simple fabrication process,low energy consumption,large specific surface area and high conductivity,has been prepared by a facile one-step carbonization.In addition,the carbon foam possesses suitable interlayer spacing in short range which is flexible to accommodate the deformation of carbon layer caused by the ion insertion and deinsertion at the charge and discharge state.Furthermore,a low cost carbon-based symmetric potassium dual-ion capacitor(PDIC),which integrates the virtues of potassium ion capacitors and dual-ion batteries,is successfully established with CFMS as both the battery-type cathode and the capacitor-type anode.PDIC displays a superior rate performance,an ultra-long cycle life(90%retention after 10000 cycles),and a high power density of 7800 W kg^-1 at an energy density of 39Whkg^-1.The PDIC also exhibits excellent ultrafast charge and slow discharge properties,with a full charge in just 60 s and a discharge time of more than 3000 s.

Cross-Linked Hollow Graphitic Carbon as Low-Cost and High-Performance Anode for Potassium Ion Batteries

Large-scale and low-cost preparation of carbon-based potassium anode with long life and high capacity is one of the footstones for the development of potassium ion batteries(PIBs).Herein,a low-cost carbon-based material,cross-linked hollow graphitic carbon(HGC),is large scale synthesized to apply for PIBs anode.Its hollow structure can afford sufficient space to overcome the damage caused by the volume expansion of graphitic carbon(GC).While the cross-linked structure forms a compact interconnection network that allows electrons to rapid transfer between different GC frameworks.Electrochemical measurements demonstrated that the HGC anode exhibited low charge/discharge plateau(about 0.25 V and 0.1 V)and excellent specific capacity as high as 298 m A h g^(-1)at the current density of 50 m A g^(-1).And more important,after 200 cycles the capacity of HGC anode still shows 269 m A h g^(-1)(the decay rate of per cycle is only 0.048%).Meanwhile,the use of commercial traditional electrolyte(KPF_(6))and cheap raw materials that provide new hope for trying and realizing the large-scale production of PIBs based on carbon anode materials.

Research on the Drought Forecast of Potato in Central Inner Mongolia Based on Precipitation Anomaly

In order to explore the method and index of potato fine drought forecast in central Inner Mongolia,based on the data of potato yield and precipitation in Wuchuan County of Hohhot City,Guyang County of Baotou City,and Chayou Middle Banner of Ulan Qab City from 1979 to 2013,the relationship between precipitation anomaly percentage and meteorological yield during potato growth period in central Inner Mongolia was analyzed by regression analysis.According to the precipitation anomaly percentage meteorological drought index,the light drought,medium drought and heavy drought indexes of the seedling stage and flowering stage in the above-mentioned areas were obtained as follows:-5%--25%,-25%--40%,and<-40%,respectively.The results show that the models are more accurate in determining the yield reduction caused by drought,and can well predict the occurrence of drought.

Quantitative Study on the Grade of Forest Combustibles Based on "3S" Technology

Based on a comprehensive and systematic analysis of the temporal and spatial distribution,periodic changes,and influencing factors of forest fires in Inner Mongolia,through fixed-point observations and experiments on the ground,forest combustibles are divided into the ground litter layer,ground standing litter,and living plants.The combustibles are divided into various grades according to their load,dryness and combustibility.By determining the influencing factors of each combustible grade,a forecast model of the combustibility grade of combustibles is established.The forecast model has been widely used in the mid-and long-term forecast model of fire danger grade,and the accuracy rate of the fall area forecast through back-generation fitting verification is above 88.43%.

锂离子动力电池热失控机理及热管理技术研究进展

锂离子动力电池作为新能源汽车的直接能量来源,对整车的安全性和耐用性起到决定性作用。随着社会发展对动力电池能量密度和使用环境要求的不断提高,以热失控为代表的动力电池安全事故频发,严重限制新能源汽车的大规模普及。因此,深入研究动力电池热失控机理并优化相应的热管理技术成为亟待解决的问题。本文从锂离子动力电池热失控现象出发,系统总结热失控的演化过程,阐明机械、热、电及内短路导致电池热失控的机制。基于此,本文全面总结目前对锂离子动力电池热管理技术的研究思路,并对未来提高锂离子动力电池系统安全性的策略进行展望。

混合体系:一种改善水系钾离子全电池能量密度和稳定性的有效方式

水系钾基电池(APBs)因具有高安全性和环境友好的性质而被广泛研究.然而,由于电极材料和工作机制的限制,APBs在倍率性能和能量密度方面需要进一步提高,以满足发展需求.针对上述问题,我们首次成功设计并组装了以Z n金属作为阳极,K1.9 2C u0.6 2M n0.3 8-[Fe(CN)6]0.968·□0.0 3 2·H_(2)O0.35作为阴极,2 mol L-1Zn(SO_(3)CF3)2+12 mol L-1KSO_(3)CF3作为电解液的水系钾基电池.这种混合离子体系的设计优点是:(i)选择金属锌作为阳极,提高了APBs的工作电位;(ii)双阳离子储存机制缩短了离子传输路径;(ⅲ)来自双阳离子电解质的K+通过静电屏蔽作用抑制了锌枝晶的生长.因此,组装后的全电池具有1.75 V的高工作电位,并具有优异的倍率性能(在10,000 mA g-1的电流密度下,保持原有容量的83.3%).此外,通过理论相场模拟和综合表征充分揭示了原位静电屏蔽效应,显著抑制了锌阳极的枝晶生长,提高了全电池稳定性.混合离子电池的结构设计为高性能APBs的发展提供了思路.

Evaluation of DNA adduct damage using G-quadruplex-based DNAzyme

Toxicity assessment is a major problem in pharmaceutical candidates and industry chemicals development.However,due to the lack of practical analytical methods for DNA adduct analysis,the safety evaluation of drug and industry chemicals was severely limited.Here,we develop a DNAzyme-based method to detect DNA adduct damage for toxicity assessment of drugs and chemicals.Among 18 structural variants of G4 DNAzyme,EA2 DNAzyme exhibits an obvious DNA damaging effect of styrene oxide(SO)due to its unstable structure.The covalent binding of SO to DNAzyme disrupts the Hoogsteen hydrogen bonding sites of G-plane guanines and affects the formation of the G4 quadruplex.DNA damage chemicals reduce the peroxidase activity of the G4 DNAzyme to monitor the DNA adduct damage by disrupting the structural integrity of the G4 DNAzyme.Our method for genotoxic assessment of pharmaceutical candidates and industrial chemicals can elucidate the complex chemical pathways leading to toxicity,predict toxic effects of chemicals,and evaluate possible risks to human health.

氮掺杂空心碳纤维用作高性能钾离子电池自支撑负极材料

本文报道了一种具有多级结构(氮掺杂团簇复合中空碳纤维)、高可逆容量的钾离子电池负极材料(NHCF@NCC).该电极材料以多孔氮掺杂中空碳纤维为骨架,具有大比表面积,可有效地缩短钾离子的扩散距离,增加电极材料与电解质的接触界面.另外,附着在中空碳纤维上的不规则的氮掺杂团簇可以提供更多的反应活性位点.由于碳纤维高的纵横比,NHCF@NCC可形成三维连通导电网络的自支撑结构.以NHCF@NCC为自支撑无衬底负极的钾离子电池表现出优异的电化学性能,100 mA g^-1电流密度下可逆容量可达310 mA hg^-1,1000次循环后容量无明显衰减.当电流密度增加到2000 mA g^-1,该自支撑电极仍具有153 mA h g^-1的可逆容量,显示了优异的倍率性能.