Br2/Br- redox couple has the advantage of higher electrode potential and lower cost, thus the bromine-based flow batteries have attracted lots of attention. However, the relatively low reactivity of Br2/Br- and crossover of Br2 are the key challenges limiting the application of bromine-based flow batteries.
　　Energy Storage Division led by Prof. ZHANG Huamin and Prof. LI Xianfeng in Dalian Institute of Chemical Physics has made significant progress in electrode materials of bromine-based flow batteries. This group proposed the idea of using "pore size exclusion" to entrapping Br2 complex, for the first time. The cage-like porous carbon with super high activity to Br2/Br- and Br2 complex entrapping capability was designed and applied in zinc bromine flow battery.
　　Figure. Principle of cage-like porous carbon applied in bromine-based batteries (Image by WANG Chenhui)
　　In this work, cage-like porous carbon material is designed, whose pore size on the shell is between Br- and Br2 complex. And the Br- can freely enter into the cage and be oxidized to Br2, which easily combines with complexing agent and further be entrapped in the cage due to the pore size exclusion. In this way, the crossover problem is efficiently suppressed and the zinc bromine flow battery assembled with the cage-like porous carbon achieves the coulombic efficiency of 98% and energy efficiency of 81% at 80 mA/cm2. This work has put forward a new idea for the design of the electrode material for the bromine-based flow batteries.(Text and Image by WANG Chenhui)
　　Dr. LU Xinyi
　　Dalian Institute of Chemical Physics, Chinese Academy of Sciences,
　　457 Zhongshan Road, Dalian, 116023, China,
　　Tel: 86-411-84379201
　　E-mail: luxinyi@dicp.ac.cn 

　　The 1st Fluorescent Probe and Imaging Symposium was held from March 31 to April 2, 2017 in Dalian Institute of Chemical Physics. This symposium had attracted more than 120 scientists and students from 32 Universities and Institutes around China, and 37 reporters made wonderful speech. The editor of Chinese Chemical Letters(CCL) Prof. QIAN Xuhong made a welcome speech by phone. The vice-editor of CCL GUO Huanfang introduced the current status of CCL. The meeting was chaired by Prof. XU Zhaochao, DICP, who introduced the two special issues of “Fluorescent Probes” and “Fluorescent Imaging” in CCL.
　　Fluorescence has been becoming one of the most powerful tools in life and materials science research. This symposium constructed a stage for young scholars in the fields of fluorescent probe and fluorescence imaging to present, share, and discuss their recent achievements and ideas. The purpose of this meeting was not only to strengthen the communications among young scholars, but also find ways to make Chinese Chemical Letters one of the world-class journals.（Text by LENG Shuang and Image by LIU Wansheng）
　　

　　The rapid development of miniaturized, flexible and wearable electronic devices has essentially stimulated the urgent demand of microscale power sources that can be directly integrated with them. Micro-supercapacitors (MSCs) with impressive power density, large storage capacity, and superior cycling lifetime are arising as a class of next-generation on-chip energy storage devices. In general, graphene-based MSCs are created by conventional lithographic microfabrication, inkjet printing, screen printing, laser-irradiation assisted method.
　　However, these techniques usually involve multiple separated steps, resulting in the complicated processes, high cost, relatively low power density, poor frequency response and low efficiency of device assembly in a large scale. As a result, developing inexpensive, single-step scalable fabrication of MSCs with both high energy and power densities is still challenging.
　　Schematic diagram showing the one-step fabrication process for PRG-MSCs with different geometries of parallel interdigital, concentric circular, two parallel strips and folding line fingers (Imaged by WANG Sen and ZHAO Xuejun)
　　To solve this issue, the scientists WU Zhongshuai, SUN Chenglin, BAO Xinhe et al from Dalian Institute of Chemical Physics developed the scalable fabrication of graphene-based monolithic MSCs with diverse planar geometries and capable of superior integration by photochemical reduction of graphene oxide/TiO2 nanoparticle hybrid films. This work has been published online in ACS Nano (DOI: 10.1021/acsnano.7b01390).
　　The as-fabricated MSCs displayed high volumetric capacitance of 233.0 F cm-3, outstanding flexibility, and remarkable capacity of modular serial and parallel integration. More importantly, by precisely engineering the interface of electrode with electrolyte, they developed high-rate graphene-based MSCs using a hydrophobic electrolyte of ionic liquid, working well at a high scan rate of 200 V s-1, two orders of magnitude higher than those of conventional supercapacitors. The MSCs showed high volumetric power density of 312 W cm-3 and energy density of 7.7 mWh cm-3, both of which are among the highest values achieved for carbon-based MSCs. More importantly, this method is highly flexible for tailoring the geometries and sizes of MSCs, and make modular integration without need of additional metal-based interconnects and contacts. Therefore, this inexpensive, single-step photoreduction strategy holds great potential for scalable production of cost-efficient, flexible and miniaturized graphene-based MSCs. (Text and Image by WANG Sen and ZHAO Xuejun)
　　Funder: This work was financially supported by the National Natural Science Foundation of China (Grant 51572259), National Key R&D Program of China (Grants 2016YBF0100100, 2016YFA0200200), Natural Science Foundation of LiaoningProvince (Grant 201602737), and DICP (Grant Y5610121T3).
　　Dr. LU Xinyi
　　Dalian Institute of Chemical Physics, Chinese Academy of Sciences,
　　457 Zhongshan Road, Dalian, 116023, China,
　　Tel: 86-411-84379201
　　E-mail: luxinyi@dicp.ac.cn 

　　The rapid development of miniaturized, flexible and wearable electronic devices has essentially stimulated the urgent demand of microscale power sources that can be directly integrated with them. Micro-supercapacitors (MSCs) with impressive power density, large storage capacity, and superior cycling lifetime are arising as a class of next-generation on-chip energy storage devices. In general, graphene-based MSCs are created by conventional lithographic microfabrication, inkjet printing, screen printing, laser-irradiation assisted method.
　　However, these techniques usually involve multiple separated steps, resulting in the complicated processes, high cost, relatively low power density, poor frequency response and low efficiency of device assembly in a large scale. As a result, developing inexpensive, single-step scalable fabrication of MSCs with both high energy and power densities is still challenging.
　　Schematic diagram showing the one-step fabrication process for PRG-MSCs with different geometries of parallel interdigital, concentric circular, two parallel strips and folding line fingers (Imaged by WANG Sen and ZHAO Xuejun)
　　To solve this issue, the scientists WU Zhongshuai, SUN Chenglin, BAO Xinhe et al from Dalian Institute of Chemical Physics developed the scalable fabrication of graphene-based monolithic MSCs with diverse planar geometries and capable of superior integration by photochemical reduction of graphene oxide/TiO2 nanoparticle hybrid films. This work has been published online in ACS Nano (DOI: 10.1021/acsnano.7b01390).
　　The as-fabricated MSCs displayed high volumetric capacitance of 233.0 F cm-3, outstanding flexibility, and remarkable capacity of modular serial and parallel integration. More importantly, by precisely engineering the interface of electrode with electrolyte, they developed high-rate graphene-based MSCs using a hydrophobic electrolyte of ionic liquid, working well at a high scan rate of 200 V s-1, two orders of magnitude higher than those of conventional supercapacitors. The MSCs showed high volumetric power density of 312 W cm-3 and energy density of 7.7 mWh cm-3, both of which are among the highest values achieved for carbon-based MSCs. More importantly, this method is highly flexible for tailoring the geometries and sizes of MSCs, and make modular integration without need of additional metal-based interconnects and contacts. Therefore, this inexpensive, single-step photoreduction strategy holds great potential for scalable production of cost-efficient, flexible and miniaturized graphene-based MSCs. (Text and Image by WANG Sen and ZHAO Xuejun)
　　Funder: This work was financially supported by the National Natural Science Foundation of China (Grant 51572259), National Key R&D Program of China (Grants 2016YBF0100100, 2016YFA0200200), Natural Science Foundation of LiaoningProvince (Grant 201602737), and DICP (Grant Y5610121T3).
　　Dr. LU Xinyi
　　Dalian Institute of Chemical Physics, Chinese Academy of Sciences,
　　457 Zhongshan Road, Dalian, 116023, China,
　　Tel: 86-411-84379201
　　E-mail: luxinyi@dicp.ac.cn 

　　The ever-increasing demand of multifunctional integrated circuitry has spawned enthusiastic quest for efficient, miniaturized, compact energy storage devices. Micro-supercapacitors (MSCs) with appealing characteristics of high power density, fast charge and discharge rate, and long lifetime are gradually acknowledged as a discrete microscale power source for directly integrating microelectronic systems on chip. Until now, tremendous efforts have been devoted to developing electric double layer capacitive nanocarbons for high-power MSCs with long cyclability and fast frequency response.
　　However, the complex porous structure of most nanocarbon electrodes and strong restacking of graphene nanosheets negatively impacts high-power handling characteristics of MSCs because of the long path of ion diffusion. To realize high-power MSCs, designing a shape-engineered electrode with short channel lengths and easy accessibility of electrolyte ions as well as strong interfacial interaction between electrode and current collector is an important and necessitating requirement.
　　High-density VG arrays for direct integration of high-power supercapacitors (Image by ZHENG Shuanghao and ZHAO Xuejun)
　　To address this, scientists WU Zhongshuai and BAO Xinhe et al at Dalian Institute of Chemical Physics, collaborated with GUO Liwei et al from Institute of Physics of CAS, developed the unidirectional arrays of high-density vertically aligned graphene (VG), derived from thermally decomposed SiC substrate, for high-power MSCs. This work has been published online in ACS Nano. (DOI: 10.1021/acsnano.7b00553).
　　The construction of high-power MSCs was based on high-density unidirectional VG arrays directly derived from thermally decomposed SiC substrate. The resulting VG arrays presented high-density structurally ordering alignment of monolayer and few-layer graphene nanosheets, edge-enriched structure, open intersheet channels, high electrical conductivity, and strong bonding of the VG edges to the SiC substrate. The fabricated VG-MSCs displayed high areal capacitance and volumetric capacitance, fast frequency response (9 ms) and excellent long-term cyclability.
　　Remarkably, VG-MSCs operated in both gel electrolyte and ionic liquid can operate well at a high scan rate of up to 200 V s-1, and showed high power density of ~61 W cm-3. Therefore, the SiC substrate is promising for large-scale production of high-density VG arrays with strong bonding to the conductive substrate, and subsequently for their direct integration of high-power super-capacitors. (Text and Image by ZHENG Shuanghao and ZHAO Xuejun)
　　Funder: National Natural Science Foundation of China, Ministry of Science and Technology of China, Natural Science Foundation of Liaoning Province, DICP, China Postdoctoral Science Foundation and dedicated funds for methanol conversion from DICP.
　　Dr. LU Xinyi
　　Dalian Institute of Chemical Physics, Chinese Academy of Sciences,
　　457 Zhongshan Road, Dalian, 116023, China,
　　Tel: 86-411-84379201
　　E-mail: luxinyi@dicp.ac.cn 
　　

　　The ever-increasing demand of multifunctional integrated circuitry has spawned enthusiastic quest for efficient, miniaturized, compact energy storage devices. Micro-supercapacitors (MSCs) with appealing characteristics of high power density, fast charge and discharge rate, and long lifetime are gradually acknowledged as a discrete microscale power source for directly integrating microelectronic systems on chip. Until now, tremendous efforts have been devoted to developing electric double layer capacitive nanocarbons for high-power MSCs with long cyclability and fast frequency response.
　　However, the complex porous structure of most nanocarbon electrodes and strong restacking of graphene nanosheets negatively impacts high-power handling characteristics of MSCs because of the long path of ion diffusion. To realize high-power MSCs, designing a shape-engineered electrode with short channel lengths and easy accessibility of electrolyte ions as well as strong interfacial interaction between electrode and current collector is an important and necessitating requirement.
　　High-density VG arrays for direct integration of high-power supercapacitors (Image by ZHENG Shuanghao and ZHAO Xuejun)
　　To address this, scientists WU Zhongshuai and BAO Xinhe et al at Dalian Institute of Chemical Physics, collaborated with GUO Liwei et al from Institute of Physics of CAS, developed the unidirectional arrays of high-density vertically aligned graphene (VG), derived from thermally decomposed SiC substrate, for high-power MSCs. This work has been published online in ACS Nano. (DOI: 10.1021/acsnano.7b00553).
　　The construction of high-power MSCs was based on high-density unidirectional VG arrays directly derived from thermally decomposed SiC substrate. The resulting VG arrays presented high-density structurally ordering alignment of monolayer and few-layer graphene nanosheets, edge-enriched structure, open intersheet channels, high electrical conductivity, and strong bonding of the VG edges to the SiC substrate. The fabricated VG-MSCs displayed high areal capacitance and volumetric capacitance, fast frequency response (9 ms) and excellent long-term cyclability.
　　Remarkably, VG-MSCs operated in both gel electrolyte and ionic liquid can operate well at a high scan rate of up to 200 V s-1, and showed high power density of ~61 W cm-3. Therefore, the SiC substrate is promising for large-scale production of high-density VG arrays with strong bonding to the conductive substrate, and subsequently for their direct integration of high-power super-capacitors. (Text and Image by ZHENG Shuanghao and ZHAO Xuejun)
　　Funder: National Natural Science Foundation of China, Ministry of Science and Technology of China, Natural Science Foundation of Liaoning Province, DICP, China Postdoctoral Science Foundation and dedicated funds for methanol conversion from DICP.
　　Dr. LU Xinyi
　　Dalian Institute of Chemical Physics, Chinese Academy of Sciences,
　　457 Zhongshan Road, Dalian, 116023, China,
　　Tel: 86-411-84379201
　　E-mail: luxinyi@dicp.ac.cn