Dey Ananta, Ramlal Vishwakarma Ravikumar, Sankar Selvasundarasekar Sam, Kundu Subrata, Mandal Amal Kumar, Das Amitava
Analytical and Environmental Science Division, Centralized Instrument Facility, CSIR-Central Salt and Marine Chemicals Research Institute Bhavnagar Gujarat-364002 India
Academy of Scientific and Innovative Research (AcSIR), CSIR - Human Resource Development Centre (HRDC) Campus Sector 19, Kamla Nehru Nagar Ghaziabad Uttar Pradesh-201 002 India.
Chem Sci. 2021 Sep 22;12(41):13878-13887. doi: 10.1039/d1sc04017k. eCollection 2021 Oct 27.
The growing energy demand with the widespread use of smart portable electronics, as well as an exponential increase in demand for smart batteries for electric vehicles, entails the development of efficient portable batteries with high energy density and safe power storage systems. Li-ion batteries arguably have superior energy density to all other traditional batteries. Developing mechanically robust solid-state electrolytes (SSEs) for lithium-ion conduction for an efficient portable energy storage unit is vital to empower this technology and overcome the safety constraints of liquid electrolytes. Herein, we report the formation of self-assembled organic nanosheets (SONs) utilizing positional isomers of small organic molecules (AM-2 and AM-3) for use as SSEs for lithium-ion conduction. Solvent-assisted exfoliation of the bulk powder yielded SONs having near-atomic thickness (∼4.5 nm) with lateral dimensions in the micrometer range. In contrast, self-assembly in the DMF/water solvent system produced a distinct flower-like morphology. Thermodynamic parameters, crystallinity, elemental composition, and nature of H-bonding for two positional isomers are established through various spectroscopic and microscopic studies. The efficiency of the lithium-ion conducting properties is correlated with factors like nanostructure morphology, ionic scaffold, and locus of the functional group responsible for forming the directional channel through H-bonding in the positional isomer. Amongst the three different morphologies studied, SONs display higher ion conductivity. In between the cationic and zwitterionic forms of the monomer, integration of the cationic scaffold in the SON framework led to higher conductivity. Amongst the two positional isomers, the -substituted carboxyl group forms a more rigid directional channel through H-bonding to favor ionic mobility and accounts for the highest ion conductivity of 3.42 × 10 S cm with a lithium-ion transference number of 0.49 at room temperature. Presumably, this is the first demonstration that signifies the importance of the cationic scaffold, positional isomers, and nanostructure morphologies in improving ionic conductivity. The ion-conducting properties of such SONs having a guanidinium-core may have significance for other interdisciplinary energy-related applications.
随着智能便携式电子产品的广泛使用，能源需求不断增长，同时电动汽车对智能电池的需求呈指数级增长，这就需要开发具有高能量密度的高效便携式电池以及安全的能量存储系统。锂离子电池的能量密度优于所有其他传统电池。开发用于锂离子传导的机械坚固的固态电解质（SSE）以实现高效的便携式储能单元，对于推动这项技术发展并克服液体电解质的安全限制至关重要。在此，我们报告了利用小分子有机位置异构体（AM - 2和AM - 3）形成自组装有机纳米片（SON），用作锂离子传导的SSE。通过溶剂辅助对块状粉末进行剥离，得到了具有近原子厚度（约4.5纳米）且横向尺寸在微米范围内的SON。相比之下，在二甲基甲酰胺/水溶剂体系中的自组装产生了独特的花状形态。通过各种光谱和显微镜研究确定了两种位置异构体的热力学参数、结晶度、元素组成以及氢键性质。锂离子传导性能的效率与纳米结构形态、离子支架以及负责通过位置异构体中的氢键形成定向通道的官能团位置等因素相关。在所研究的三种不同形态中，SON表现出更高的离子电导率。在单体的阳离子形式和两性离子形式之间，阳离子支架整合到SON框架中导致了更高的电导率。在两种位置异构体中，取代羧基通过氢键形成更刚性的定向通道，有利于离子迁移，在室温下锂离子迁移数为0.49时，离子电导率最高可达3.42×10 S cm。据推测，这是首次证明阳离子支架、位置异构体和纳米结构形态在提高离子电导率方面的重要性。这种具有胍基核心的SON的离子传导性能可能对其他跨学科能源相关应用具有重要意义。
