X. Y. D. Soo, J. K. Muiruri, J. Yeo, Z. M. Png, Anqi Sng, Huiqing Xie, R. Ji, Suxi Wang, Hongfei Liu, Jianwei Xu, X. Loh, Q. Yan, Zibiao Li, Qiang Zhu
Phase change materials (PCMs) are promising thermal energy storage materials due to their high specific latent heat. Conventional PCMs typically exploit the solid–liquid (s–l) transition. However, leakage and leaching are common issues for solid–liquid PCMs, which have to be addressed before usage in practical applications. In contrast, solid–solid (s–s) PCMs would naturally overcome these issues due to their inherent form stability and homogeneity. In this study, we report a new type of s–s PCM based on chemically linked polyethylene glycol (PEG, the PCM portion) with polylactic acid (PLA, the support portion) in the form of a block co‐polymer. Solid‐solid latent heat of up to 56 J/g could be achieved, with melting points of between 44 °C and 55 °C. For comparison, PEG was physically mixed into a PLA matrix to form a PEG:PLA composite. However, the composite material saw leakage of up to 9% upon heating, with a corresponding loss in thermal storage capacity. In contrast, the mPEG/PLA block co‐polymers were found to be completely homogeneous and thermally stable even when heated above its phase transition temperature, with no observable leakage, demonstrating the superiority of chemical linking strategies in ensuring form stability.
{"title":"Polyethylene glycol/polylactic acid block co‐polymers as solid–solid phase change materials","authors":"X. Y. D. Soo, J. K. Muiruri, J. Yeo, Z. M. Png, Anqi Sng, Huiqing Xie, R. Ji, Suxi Wang, Hongfei Liu, Jianwei Xu, X. Loh, Q. Yan, Zibiao Li, Qiang Zhu","doi":"10.1002/smm2.1188","DOIUrl":"https://doi.org/10.1002/smm2.1188","url":null,"abstract":"Phase change materials (PCMs) are promising thermal energy storage materials due to their high specific latent heat. Conventional PCMs typically exploit the solid–liquid (s–l) transition. However, leakage and leaching are common issues for solid–liquid PCMs, which have to be addressed before usage in practical applications. In contrast, solid–solid (s–s) PCMs would naturally overcome these issues due to their inherent form stability and homogeneity. In this study, we report a new type of s–s PCM based on chemically linked polyethylene glycol (PEG, the PCM portion) with polylactic acid (PLA, the support portion) in the form of a block co‐polymer. Solid‐solid latent heat of up to 56 J/g could be achieved, with melting points of between 44 °C and 55 °C. For comparison, PEG was physically mixed into a PLA matrix to form a PEG:PLA composite. However, the composite material saw leakage of up to 9% upon heating, with a corresponding loss in thermal storage capacity. In contrast, the mPEG/PLA block co‐polymers were found to be completely homogeneous and thermally stable even when heated above its phase transition temperature, with no observable leakage, demonstrating the superiority of chemical linking strategies in ensuring form stability.","PeriodicalId":21794,"journal":{"name":"SmartMat","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84299028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Metal–sulfur battery, which provides considerable high energy density at a low cost, is an appealing energy‐storage technology for future long‐range electric vehicles and large‐scale power grids. One major challenge of metal–sulfur batteries is their long‐term cycling stability, which is significantly deteriorated by the generation of various soluble polysulfide intermediates and the shuttling of these intermediates through the separator. Furthermore, the intrinsically sluggish reaction kinetics associated with the poor conductivity of sulfur/sulfides family causes a large polarization in cycle behavior, which further deteriorates the electrode rechargeability. To solve these problems, the research communities have spent a great amount of effort on designing smart cathodes to delicately tailor the physiochemical interaction between the sulfur hosts and polysulfides. Here, we summarize the key progress in the development of two‐dimensional (2D) host materials showing advantageous tunability of their physiochemical properties through coordination control methods such as defect engineering, heteroatom doping, heterostructure, and phase and interface engineering. Accordingly, we discuss the mechanisms of polysulfide anchoring and catalyzing upon specific coordination environment in conjunction with possible structure–property relationships and theoretical analysis. This review will provide prospective fundamental guidance for future sulfur host design and beyond.
{"title":"Advanced two‐dimensional materials toward polysulfides regulation of metal–sulfur batteries","authors":"Haining Fan, Wenbin Luo, Shixue Dou, Zijian Zheng","doi":"10.1002/smm2.1186","DOIUrl":"https://doi.org/10.1002/smm2.1186","url":null,"abstract":"Metal–sulfur battery, which provides considerable high energy density at a low cost, is an appealing energy‐storage technology for future long‐range electric vehicles and large‐scale power grids. One major challenge of metal–sulfur batteries is their long‐term cycling stability, which is significantly deteriorated by the generation of various soluble polysulfide intermediates and the shuttling of these intermediates through the separator. Furthermore, the intrinsically sluggish reaction kinetics associated with the poor conductivity of sulfur/sulfides family causes a large polarization in cycle behavior, which further deteriorates the electrode rechargeability. To solve these problems, the research communities have spent a great amount of effort on designing smart cathodes to delicately tailor the physiochemical interaction between the sulfur hosts and polysulfides. Here, we summarize the key progress in the development of two‐dimensional (2D) host materials showing advantageous tunability of their physiochemical properties through coordination control methods such as defect engineering, heteroatom doping, heterostructure, and phase and interface engineering. Accordingly, we discuss the mechanisms of polysulfide anchoring and catalyzing upon specific coordination environment in conjunction with possible structure–property relationships and theoretical analysis. This review will provide prospective fundamental guidance for future sulfur host design and beyond.","PeriodicalId":21794,"journal":{"name":"SmartMat","volume":"121 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73465754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jinzhou Fu, Hanwei Wang, Zhichen Du, Yao Liu, Qingfeng Sun, Huiqiao Li
The safety issues of lithium‐ion batteries have received attention because flammable organic electrolytes are used. Also, the commercial polyolefin separator will undergo severe thermal shrinkage when the internal temperature of the battery increases to 130–160°C, which increases the risk. Therefore, the development of a high thermal stability and high‐safety separator is an effective strategy to improve battery safety. Herein, we design a green, cellulose‐based separator (Cel@DBDPE) with a unique encapsulation structure for lithium‐ion batteries, in which functional flame retardants (DBDPE) are wrapped in microscrolls formed by the self‐rolling of 2D cellulose nanosheets upon freeze‐drying. This structure can firmly anchor DBDPE particles in the separator to prevent them from undergoing exfoliation and does not affect the properties of the separator, such as the thickness and the pore structure. Compared with commercial polypropylene, Cel@DBDPE has excellent thermal stability and flame retardancy. The former makes it less prone to thermal shrinkage and the latter can effectively prevent the combustion of the electrolyte, showing an efficient self‐extinguishing ability. Moreover, the Cel@DBDPE is only 15 μm in size and has competitive properties comparable to polypropylene. Thus, there is no sacrifice in the electrochemical performance of battery when the Cel@DBDPE is used as separator. This study provides a new structural design for the construction of a high‐safety separator.
{"title":"A high‐safety, flame‐retardant cellulose‐based separator with encapsulation structure for lithium‐ion battery","authors":"Jinzhou Fu, Hanwei Wang, Zhichen Du, Yao Liu, Qingfeng Sun, Huiqiao Li","doi":"10.1002/smm2.1182","DOIUrl":"https://doi.org/10.1002/smm2.1182","url":null,"abstract":"The safety issues of lithium‐ion batteries have received attention because flammable organic electrolytes are used. Also, the commercial polyolefin separator will undergo severe thermal shrinkage when the internal temperature of the battery increases to 130–160°C, which increases the risk. Therefore, the development of a high thermal stability and high‐safety separator is an effective strategy to improve battery safety. Herein, we design a green, cellulose‐based separator (Cel@DBDPE) with a unique encapsulation structure for lithium‐ion batteries, in which functional flame retardants (DBDPE) are wrapped in microscrolls formed by the self‐rolling of 2D cellulose nanosheets upon freeze‐drying. This structure can firmly anchor DBDPE particles in the separator to prevent them from undergoing exfoliation and does not affect the properties of the separator, such as the thickness and the pore structure. Compared with commercial polypropylene, Cel@DBDPE has excellent thermal stability and flame retardancy. The former makes it less prone to thermal shrinkage and the latter can effectively prevent the combustion of the electrolyte, showing an efficient self‐extinguishing ability. Moreover, the Cel@DBDPE is only 15 μm in size and has competitive properties comparable to polypropylene. Thus, there is no sacrifice in the electrochemical performance of battery when the Cel@DBDPE is used as separator. This study provides a new structural design for the construction of a high‐safety separator.","PeriodicalId":21794,"journal":{"name":"SmartMat","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73439386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lithium metal batteries (LMBs) have attracted considerable interest for use in electric vehicles and as next‐generation energy storage devices because of their high energy density. However, a significant practical drawback with LMBs is the instability of the Li metal/electrolyte interface, with concurrent parasitic reactions and dendrite growth, that leads to low Coulombic efficiency and poor cycle life. Owing to the significant role of electrolytes in batteries, rationally designed electrolytes can improve the electrochemical performance of LMBs and possibly achieve fast charge and a wide range of working temperatures to meet various requirements of the market in the future. Although there are some review papers about electrolytes for LMBs, the focus has been on a single parameter or single performance separately and, therefore, not sufficient for the design of electrolytes for advanced LMBs for a wide range of working environments. This review presents a systematic summary of recent progress made in terms of electrolytes, covering the fundamental understanding of the mechanism, scientific challenges, and strategies to address drawbacks of electrolytes for high‐performance LMBs. The advantages and disadvantages of various electrolyte strategies are also analyzed, yielding suggestions for optimum properties of electrolytes for advanced LMBs applications. Finally, the most promising research directions for electrolytes are discussed briefly.
{"title":"Recent progress in electrolyte design for advanced lithium metal batteries","authors":"Mingnan Li, Caoyu Wang, K. Davey, Jingxi Li, Guanjie Li, Shilin Zhang, Jianfeng Mao, Zaiping Guo","doi":"10.1002/smm2.1185","DOIUrl":"https://doi.org/10.1002/smm2.1185","url":null,"abstract":"Lithium metal batteries (LMBs) have attracted considerable interest for use in electric vehicles and as next‐generation energy storage devices because of their high energy density. However, a significant practical drawback with LMBs is the instability of the Li metal/electrolyte interface, with concurrent parasitic reactions and dendrite growth, that leads to low Coulombic efficiency and poor cycle life. Owing to the significant role of electrolytes in batteries, rationally designed electrolytes can improve the electrochemical performance of LMBs and possibly achieve fast charge and a wide range of working temperatures to meet various requirements of the market in the future. Although there are some review papers about electrolytes for LMBs, the focus has been on a single parameter or single performance separately and, therefore, not sufficient for the design of electrolytes for advanced LMBs for a wide range of working environments. This review presents a systematic summary of recent progress made in terms of electrolytes, covering the fundamental understanding of the mechanism, scientific challenges, and strategies to address drawbacks of electrolytes for high‐performance LMBs. The advantages and disadvantages of various electrolyte strategies are also analyzed, yielding suggestions for optimum properties of electrolytes for advanced LMBs applications. Finally, the most promising research directions for electrolytes are discussed briefly.","PeriodicalId":21794,"journal":{"name":"SmartMat","volume":"80 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91290771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ziqing Hu, Hanwei Zhang, Hui Liu, Jinsa Li, Xiaofan Ji, Ben Zhong Tang
{"title":"AIE gel exhibiting continuous gradient fluorescence based on a polar‐responsive AIE‐gen","authors":"Ziqing Hu, Hanwei Zhang, Hui Liu, Jinsa Li, Xiaofan Ji, Ben Zhong Tang","doi":"10.1002/smm2.1184","DOIUrl":"https://doi.org/10.1002/smm2.1184","url":null,"abstract":"","PeriodicalId":21794,"journal":{"name":"SmartMat","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79023652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daqing He, M. Zeng, Zhenzhen Zhang, Yong-Ju Bai, Guichuan Xing, Hui‐Ming Cheng, Yuze Lin
{"title":"Exciton diffusion and dissociation in organic and quantum‐dot solar cells","authors":"Daqing He, M. Zeng, Zhenzhen Zhang, Yong-Ju Bai, Guichuan Xing, Hui‐Ming Cheng, Yuze Lin","doi":"10.1002/smm2.1176","DOIUrl":"https://doi.org/10.1002/smm2.1176","url":null,"abstract":"","PeriodicalId":21794,"journal":{"name":"SmartMat","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78420911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Highly conductive fiber with design of dual conductive Ag/CB layers for ultrasensitive and wide‐range strain sensing","authors":"Ben Niu, Su Yang, Yiyi Yang, T. Hua","doi":"10.1002/smm2.1178","DOIUrl":"https://doi.org/10.1002/smm2.1178","url":null,"abstract":"","PeriodicalId":21794,"journal":{"name":"SmartMat","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82228672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stretchable and reconfigurable artificial synaptic devices with both excitatory and inhibitory properties have a wide range of applications and requirements in high‐performance neuromorphic computing and wearable electronics. Shim et al. have realized reconfigurable synaptic transistors with excitatory and inhibitory properties in the stretched state through elastic bilayer semiconductors, demonstrating great potential for neuromorphic computing.
{"title":"A stretchable and reconfigurable synaptic transistor","authors":"Dongyang Zhu, Deyang Ji","doi":"10.1002/smm2.1179","DOIUrl":"https://doi.org/10.1002/smm2.1179","url":null,"abstract":"Stretchable and reconfigurable artificial synaptic devices with both excitatory and inhibitory properties have a wide range of applications and requirements in high‐performance neuromorphic computing and wearable electronics. Shim et al. have realized reconfigurable synaptic transistors with excitatory and inhibitory properties in the stretched state through elastic bilayer semiconductors, demonstrating great potential for neuromorphic computing.","PeriodicalId":21794,"journal":{"name":"SmartMat","volume":"310 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76440613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}