Ji Peiyuan, Zhang Chengshuang, Wan Jing, Zhou Meili, Xi Yi, Guo Hengyu, Hu Chenguo, Gu Xiao, Wang Chuanshen, Xue Wendong
Department of Applied Physics, State Key Laboratory of Power Transmission Equipment & System Security and New Technology , Chongqing University , Chongqing 400044 , China.
School of Materials Science and Engineering , University of Science and Technology Beijing , Beijing 100083 China.
ACS Appl Mater Interfaces. 2019 Aug 14;11(32):28900-28908. doi: 10.1021/acsami.9b08350. Epub 2019 Aug 2.
Nanomaterials with tunnel structures are extremely attractive to be used for electrode materials in electrochemical energy storage devices. Tunnel-structured Ti-doped NaMnO nanoparticles (TNMO-NPs) were synthesized by a facile and high-production method of the solid-state reaction with a high-energy ball-milling process. As electrode materials in the supercapacitor cell, the as-synthesized TNMO-NPs exhibit a high specific capacity of 284.93 mA h g (0.57 mA h cm/1025.75 F g). A superior rate capability with a decay of 36% is achieved by increasing the scan rates from 2 to 25 mV s. To further explore the storage mechanism of Ti-doped NaMnO materials, density functional theory (DFT) calculations were used to calculate the activation energy for the ion immigration in the electrode, and the results show that the minimum ion diffusion barrier energy is 0.272 eV, indicating that the sodium ions could insert into the system easily. Through the scan-rate-dependent cyclic voltammetry analysis, the capacity value indicates a mixed charge storage of capacitive behavior and Na intercalation progress. A maximum energy density of 77.81 W h kg at a power density of 125 W kg is achieved, and a high energy density of 54.79 W h kg is maintained even at an ultrahigh power density of 3750 W kg. The TNMO-NP supercapacitors show excellent flexibility at various bent (0-180°) states. The capacitive performance of the TNMO-NPs makes them promising cathode materials for flexible supercapacitors with high specific capacities and high energy densities.
具有隧道结构的纳米材料作为电化学储能装置的电极材料极具吸引力。通过高能球磨固态反应的简便高产方法合成了隧道结构的Ti掺杂NaMnO纳米颗粒（TNMO-NPs）。作为超级电容器电池中的电极材料，合成的TNMO-NPs表现出284.93 mA h g（0.57 mA h cm/1025.75 F g）的高比容量。通过将扫描速率从2 mV s提高到25 mV s，实现了36%衰减的优异倍率性能。为了进一步探索Ti掺杂NaMnO材料的存储机制，使用密度泛函理论（DFT）计算来计算电极中离子迁移的活化能，结果表明最小离子扩散势垒能量为0.272 eV，表明钠离子可以很容易地插入系统。通过扫描速率相关的循环伏安分析，容量值表明电容行为和Na嵌入过程的混合电荷存储。在功率密度为125 W kg时实现了77.81 W h kg的最大能量密度，即使在3750 W kg的超高功率密度下也保持了54.79 W h kg的高能量密度。TNMO-NP超级电容器在各种弯曲（0-180°）状态下表现出优异的柔韧性。TNMO-NPs的电容性能使其成为具有高比容量和高能量密度的柔性超级电容器的有前景的阴极材料。
