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A strategy based on water soluble coal tar pitches to construct MnO_(2)@C composite materials with high electrochemical performance

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Science China(Technological Sciences) 2024年第1期67卷 311-320页

作者： LIU Bo WANG Kun GUO ZhaoQi HAN BeiBei XU GuiYing ju DongYing AN BaiGang LI YongCheng NI ZhenYong ZHOU weimin Key Laboratory of Energy Materials and Electrochemistry Research Liaoning Province University of Science and Technology LiaoningAnshan 114051China Advanced Science Research Laboratory Saitama Institute of TechnologyFusaiji 1690Japan Liaoning Starry Sky Sodium Battery Co. Ltd.Anshan 114051China Sinosteel Anshan Research Institute of Thermo-Energy Co. Ltd.Anshan 114051China State Key Laboratory of Marine Resource Utilization in South China Sea Hainan Provincial Key Lab of Fine ChemistrySchool of Chemical Engineering and TechnologyHainan UniversityHaikou 570228China Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of Zhejiang Province Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China

The water soluble coal tar pitches(WS-CTPs)were successfully prepared and used to construct the MnO_(2)@C composite materials by a hydrothermal method.It is interestingly observed that the structures and morphologies of MnO_(2)@C materials can be controlled by controlling the dosages of WS-CTPs and KMnO4.Meanwhile,it is aware that MnO_(2)exists in the MnO_(2)@C materials in an amorphous state.Compared with MnO_(2),MnO_(2)@C materials output a remarkable improvement in electrochemical performance.For instance,MnO_(2)@C-0.3 shows the storage capacity at 965.7 mA h g^(−1)after 300 cycles at a current density of 0.1 A g^(−1).In addition,after 600 cycles at a current density of 1.0 A g^(−1),the storage capacity of MnO_(2)@C-0.3 still keeps 450.3 mA h g^(−1),indicating that MnO_(2)@C-0.3 owns tremendous cycle stability at a high current density.In view of the fact that the coal tar pitches possess great cost advantages,the strategy of using WS-CTPs as a carbon source to cover the metal oxides is a competitive way to expand the application of metal oxides in the fabrication of electrodes of LIBs.

关键词： water soluble coal tar pitches MnO_(2) composite materials lithium ion batteries(LIBs) energy storage systems(ESSs) coal tar pitches

Effects of a Remotely Sensed Land Cover Dataset with High Spatial Resolution on the Simulation of Secondary Air Pollutants over China Using the Nested-grid GEOS-Chem Chemical Transport Model

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Advances in Atmospheric Sciences 2014年第1期31卷 179-187页

作者： LI Mingwei WANG Yuxuan ju weimin Ministry of Education Key Laboratory for Earth System Modeling Center for Earth System Science Institute for Global Change Studies Tsinghua University School of Environment Tsinghua University International Institute for Earth System Science Nanjing University

A number of remotely sensed land cover datasets with spatial resolutions ~〈 1 km have recently become available or are in the process of being mapped. The application of these higher resolution and more up-to-date land cover datasets in chemical transport models （CTMs） is expected to improve the simulation of dry deposition and biogenic emissions of non-methane volatile organic compounds （NMVOCs）, which affect ozone and other secondary air pollutants. In the present study, we updated the land cover dataset in the nested-grid GEOS-Chem CTM with the 1 km resolution GLC2000 land cover map and examined the resulting changes in the simulation of surface ozone and sulfate over China in july 2007. Through affecting the dry deposition velocities of ozone and its precursors, using GLC2000 in the dry deposition module can decrease the simulated surface ozone by 3% （up to 6 ppb） over China. Simulated surface sulfate shows an increase of 3% in northwestern China and a decrease of 1% in northern China. Applying GLC2000 in the biogenic emissions of the NMVOC module can lead to a 0.5--4.5 ppb increase in simulated surface ozone over East China, mainly driven by the larger cove~：age of broadleaf trees in East China in the GLC2000 dataset. Our study quantifies the large sensitivity to land cover dataset~ with different spatial resolutions and time periods of simulated secondary air pollutants over China, supporting ongoing research efforts to produce high resolution and dynamically updated land cover datasets over China, as well as for the globe.

关键词： land cover dry deposition biogenic emissions ozone sulfate

Climate effects of the GlobeLand30 land cover dataset on the Beijing Climate Center climate model simulations

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Science China Earth Sciences 2016年第9期59卷 1754-1764页

作者： SHI XueLi NIE SuPing ju weimin YU Le National Climate Center Beijing 100081 China International Institute for Earth System Science (ESSI) Nanjing University Nanjing 210093 China Ministry of Education Key Laboratory for Earth System Modeling Center for Earth System Science Tsinghua University Beijing 100084 China Joint Center for Global Change Studies Beijing 100875 China

Land cover is one of the most basic input elements of land surface and climate models. Currently, the direct and indirect effects of land cover data on climate and climate change are receiving increasing attentions. In this study, a high resolution(30 m) global land cover dataset(Globe Land30) produced by Chinese scientists was, for the first time, used in the Beijing Climate Center Climate System Model(BCC_CSM) to assess the influences of land cover dataset on land surface and climate simulations. A two-step strategy was designed to use the Globe Land30 data in the model. First, the Globe Land30 data were merged with other satellite remote sensing and climate datasets to regenerate plant functional type(PFT) data fitted for the BCC_CSM. Second, the up-scaling based on an area-weighted approach was used to aggregate the fine-resolution Globe Land30 land cover type and area percentage with the coarser model grid resolutions globally. The Globe Land30-based and the BCC_CSM-based land cover data had generally consistent spatial distribution features, but there were some differences between them. The simulation results of the different land cover type dataset change experiments showed that effects of the new PFT data were larger than those of the new glaciers and water bodies(lakes and wetlands). The maximum value was attained when dataset of all land cover types were changed. The positive bias of precipitation in the mid-high latitude of the northern hemisphere and the negative bias in the Amazon, as well as the negative bias of air temperature in part of the southern hemisphere, were reduced when the Globe Land30-based data were used in the BCC_CSM atmosphere model. The results suggest that the Globe Land30 data are suitable for use in the BCC_CSM component models and can improve the performance of the land and atmosphere simulations.

关键词：土地覆盖类型气候影响数据集模式模拟北京面积加权法气候模型陆地表面

Spatio-temporal dynamics of vegetation and its relationship with climate factors Mongolia, China coverage in Inner

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Journal of Geographical Sciences 2013年第2期23卷 231-246页

作者： MU Shaojie YANG Hongfei LI Jianlong CHEN Yizhao GANG Chengcheng ZHOU Wei ju weimin SchoolofLifeScience NamingUniversityNanjing210093China InternationalInstituteforEarth-SystemScience N-anjinguniversityNanjing210093China

The vegetation coverage dynamics and its relationship with climate factors on different spatial and temporal scales in Inner Mongolia during 2001-2010 were analyzed based on MODIS-NDVI data and climate data. The results indicated that vegetation coverage in Inner Mongolia showed obvious longitudinal zonality, increasing from west to east across the region with a change rate of 0.2/10N. During 2001-2010, the mean vegetation coverage was 0.57, 0.4 and 0.16 in forest, grassland and desert biome, respectively, exhibiting evident spatial heterogeneities. Totally, vegetation coverage had a slight increasing trend during the study period. Across Inner Mongolia, the area of which the vegetation coverage showed extremely significant and significant increase accounted for 11.25% and 29.13% of the area of whole region, respectively, while the area of which the vegetation coverage showed extremely significant and significant decrease accounted for 7.65% and 26.61%, respectively. On interannual time scale, precipitation was the dominant driving force of vegetation coverage for the whole region. On inter-monthly scale, the change of vegetation coverage was consistent with both the change of temperature and precipitation, implying that the vegetation growth within a year is more sensitive to the combined effects of water and heat rather than either single climate factor. The vegetation coverage in forest biome was mainly driven by temperature on both inter-annual and inter-monthly scales, while that in desert biome was mainly influenced by precipitation on both the two temporal scales. In grassland biome, the yearly vegetation coverage had a better correlation with precipitation, while the monthly vegetation coverage was influenced by both temperature and precipitation. In grassland bi- ome, the impacts of precipitation on monthly vegetation coverage showed time-delay effects.

关键词： Inner Mongolia vegetation coverage precipitation temperature correlation

Spatial and temporal variations of forest LAI in China during 2000-2010

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Chinese Science Bulletin 2012年第22期57卷 2846-2856页

作者： LIU YiBo ju weimin CHEN JingMing ZHU GaoLong XING BaiLing ZHU JingFang HE MingZhu International Institute for Earth System Sciences Nanjing UniversityNanjing 210093China Department of Geography Minjiang UniversityFuzhou 350108China

Forests are crucial terrestrial ecosystems.Their leaf area index (LAI) is a key parameter determining the exchange of matter and energy between the atmosphere and the ground surface.In this study,MOD 09A1 and MCD 43A1 data were input into an inversion model based on the 4-scale geometric optical model to retrieve 8-d 500 m LAI products in China during the period 2000 to 2010.The resulting LAI product was validated using LAI measured in 6 typical areas.The spatial and temporal variations of forest LAI and its relationships with temperature and precipitation were analyzed.The results show that the accuracy of the 500 m LAI product was above 70% in the 6 typical areas,indicating the reliability of this product.From 2000 to 2010,forest LAI in northeast,north,and south central China showed increasing trends.However,forest LAI in southeast and parts of southwest China showed downward trends,mainly because of the significant decrease observed during the period 2008 to 2010.Annual mean forest LAI positively correlated with annual mean temperature (AMT) in northeastern China and negatively correlated with AMT in southwest China.It had positive correlations with annual total precipitation in central south and north China.The abnormal climate conditions in 2001 and 2009 caused forest LAI to be obviously lower than normal in regions south of the Qinling Mountains and Huaihe River.Annual mean LAI decreased by more than 1.0 in some areas.

关键词：中国西南部 LAI 时间变化森林空间中国东北地区年平均气温叶面积指数

Fluoridation routes,function mechanism and application of fluorinated/fluorine-doped nanocarbon-based materials for various batteries:A review

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Journal of Energy Chemistry 2023年第10期85卷 363-393,I0011页

作者： Weicui Liu Nanping Deng Gang Wang Ruru Yu Xiaoxiao Wang Bowen Cheng Jingge ju weimin Kang State Key Laboratory of Separation Membranes and Membrane Processes/National Center for International Joint Research on Separation Membranes School of Textile Science and EngineeringTiangong UniversityTianjin 300387China School of Material Science and Engineering Tiangong UniversityTianjin 300387China

With the popularity and widespread applications of electronics,higher demands are being placed on the performance of battery materials.Due to the large difference in electronegativity between fluorine and carbon atoms,doping fluorine atoms in nanocarbon-based materials is considered an effective way to improve the performance of used battery.However,there is still a blank in the systematic review of the mechanism and research progress of fluorine-doped nanostructured carbon materials in various batteries.In this review,the synthetic routes of fluorinated/fluorine-doped nanocarbon-based(CF_x)materials under different fluorine sources and the function mechanism of CF_x in various batteries are reviewed in detail.Subsequently,judging from the dependence between the structure and electrochemical performance of nanocarbon sources,the progress of CF_x based on different dimensions(0D–3D)for primary battery applications is reviewed and the balance between energy density and power density is critically discussed.In addition,the roles of CF_x materials in secondary batteries and their current applications in recent years are summarized in detail to illustrate the effect of introducing F atoms.Finally,we envisage the prospect of CF_x materials and offer some insights and recommendations to facilitate the further exploration of CF_x materials for various high-performance battery applications.

关键词： Nanocarbon materials Fluorinated/fluorine-doped effect Function mechanism Various batteries

Hierarchical pomegranate-structure design enables stress management for volume release of Si anode

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Journal of Materials Science & Technology 2023年第26期157卷 1-10页

作者： Fang Di Zhenxing Wang Chong Ge Lixiang Li Xin Geng Chengguo Sun Haiming Yang weimin Zhou Dongying ju Baigang An Feng Li Key Laboratory of Energy Materials and Electrochemistry Liaoning Province School of Chemical EngineeringUniversity of Science and Technology LiaoningAnshan 114051China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China Hainan Provincial Key Lab of Fine Chemistry School of Chemical Engineering and TechnologyHainan UniversityHaikou 570228China Jihua Laboratory Guangdong ProvinceFoshan 528200China

Si is a promising anode material for lithium-ion batteries owing to its high theoretical capacity.How-ever,large stress during(de)lithiation induces severe structural pulverization,electrical contact failure,and unstable solid-electrolyte interface,which hampers the practical application of Si anode.Herein,a Si-based anode with a hierarchical pomegranate-structure(HPS-Si)was designed to modulate the stress variation,and a sub-micronized Si-based sphere was assembled by the nano-sized Si nanospheres with sub-nanometer-sized multi-phase modification of the covalently linked SiO_(2-x),SiC,and carbon.The sub-micronized HPS-Si stacked with Si nanospheres can avoid agglomerates during cycling due to the high surface energy of nanomaterials.Meanwhile,the reasonable pore structure from SiO_(2) reduction owing to density difference is enough to accommodate the limited volume expansion.The Si spheres with a size of about 50 nm can prevent self-cracking.SiO_(2-x),and SiC as flexible and rigid layers,have been syner-gistically used to reduce the surface stress of conductive carbon layers to avoid cracking.The covalent bonding immensely strengthens the link of the modification with Si nanospheres,thus resisting stress effects.Consequently,a full cell comprising an HPS-Si anode and a LiCoO_(2) cathode achieved an energy density of 415 Wh kg^(-1) with a capacity retention ratio of 87.9%after 300 cycles based on the active ma-terials.It is anticipated that the hierarchical pomegranate-structure design can provide inspiring insights for further studies of the practical application of silicon anode.

关键词： Stress management Silicon anode Hierarchical structure Covalent bonding Volume release

3D spiny AlF_(3)/Mullite heterostructure nanofiber as solid-state polymer electrolyte fillers with enhanced ionic conductivity and improved interfacial compatibility

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Journal of Energy Chemistry 2023年第1期76卷 503-515,I0013页

作者： Weicui Liu Lingshuai Meng Xueqiang Liu Lu Gao Xiaoxiao Wang junbao Kang Jingge ju Nanping Deng Bowen Cheng weimin Kang State Key Laboratory of Separation Membranes and Membrane Processes/National Center for International Joint Research on Separation Membranes School of Textile Science and Engineering Tiangong UniversityTianjin 300387China Institute of Systems Engineering Beijing 100010Chin

Lithium metal batteries assembled with solid-state electrolyte can offer high safety and volumetric energy density compared to liquid electrolyte.The polymer solid-state electrolytes of poly(ethylene oxide)(PEO)are widely used in lithium metal solid-state batteries due to their unique properties.However,there are still some defects such as low ionic conductivity at room temperature and weak inhibition of lithium dendrite growth.Herein,the spiny inorganic nanofibers heterostructure with mullite whiskers grown on the surface of aluminum fluoride(AlF_(3))nanofibers are introduced into the PEOLi TFSI electrolytes for the first time to prepare composite solid-state electrolytes.The AlF_(3)as a strong Lewis acid can adsorb anions and promote the dissociation of Li salts.Besides,the specially threedimensional(3D)structure enlarges the effective contacting interface with the PEO polymer,which allows the lithium ions to be transported not only along the large aspect ratio of AlF3nanofibers,but also along the mullite phase in the transmembrane direction rapidly.Thereby,the transport channel of lithium ions at the spiny inorganic nanofibers-polymer interface is further improved.Benefiting from these advantages,the obtained composite solid-state electrolyte has a high ionic conductivity of 1.58×10^(-4)S cm^(-1)at 30℃and the lithium ions transfer number of 0.53.In addition,the AlF3has strong binding energy with anions,low electronic conductivity and wide electrochemical stability window,and reduced nucleation overpotential of lithium during cycling,which is positive for lithium dendrite suppression in solid-state electrolytes.Thus,the assembled symmetric Li/Li symmetric batteries exhibit stable cycling performance at different area capacities of 0.15,0.2,0.3 and 0.4 m A h cm^(-2).More importantly,the LiFePO_(4)(LFP)/Li battery still has 113.5 m A h g-1remaining after 400 cycles at 50℃and the Coulomb efficiency is nearly 100%during the long cycle.Overall,the interconnected structure of 3D spiny inorganic heterostructure nanofi

关键词： 3D spiny inorganic nanofibers Heterostructures Composite solid-state electrolytes Ionic conductivity

The status of carbon neutrality of the world’s top 5 CO_(2) emitters as seen by carbon satellites

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Fundamental Research 2022年第3期2卷 357-366页

作者： Fei Jian Wei He weimin ju Hengmao Wang Mousong Wu jun Wang Shuzhuang Feng Lingyu Zhang Jing MChen Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology International Institute for Earth System ScienceNanjing UniversityNanjing 210023China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China Department of Geography University of TorontoTorontoOntario M5S3G3Canada Frontiers Science Center for Critical Earth Material Cycling Nanjing UniversityNanjing 210023China

China,the Unite States(US),the European Union(EU),India,and Russia are the world’s top 5 fossil fuel and cement CO_(2)(FFC)emitting countries or regions(CRs).It is very important to understand their status of carbon neutrality,and to monitor their future changes of net carbon fluxes(NCFs).In this study,we implemented a well-established global carbon assimilation system(GCAS,Version 2)to infer global surface carbon fluxes from May 2009 to December 2019 using both GOSAT and OCO-2 XCO_(2)retrievals.The reductions of flux uncertainty and XCO_(2)bias,and the evaluation of posterior flux show that GCAS has comparable and good performance in the 5 CRs.The results suggest that Russia has achieved carbon neutrality,but the other 4 are still far from being carbon neutral,especially China.The mean annual NCFs in China,the US,the EU,India,and Russia are 2.33±0.29,0.82±0.20,0.42±0.16,0.50±0.12,and-0.33±0.23 PgC yr^(−1),respectively.From 2010 to 2019,the NCFs showed an increasing trend in the US and India,a slight downward trend after 2013 in China,and were stable in the EU.The changes of land sinks in China and the US might be the main reason for their trends.India’s trend was mainly due to the increase of FFC emission.The relative contributions of NCFs to the global land net carbon emission of China and the EU have decreased,while those of the US and India have increased,implying the US and India must take more active measures to control carbon emissions or increase their sinks.This study indicates that satellite XCO_(2)could be successfully used to monitor the changes of regional NCFs,which is of great significance for major countries to achieve greenhouse gas control goals.

关键词： Net carbon flux GOSAT OCO-2 XCO_(2) Atmospheric inversion