Tang Chao, Min Yuxiang, Chen Chongyang, Xu Weiwei, Xu Lai
Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , 199 Ren'ai Road , Suzhou , 215123 , Jiangsu , PR China.
Nano Lett. 2019 Aug 14;19(8):5577-5586. doi: 10.1021/acs.nanolett.9b02115. Epub 2019 Jul 16.
Na-ion batteries are viewed as the alternative to Li-ion batteries for similar electrochemical properties, while they always suffer from a low capacity. Na-O batteries are important due to their high energy density; however, they are usually limited by high overpotential. In this manuscript, 16 different heterostructures of TMDs with MXenes (bare and O-terminated case) are constructed and their potential in the application of sodium-ion batteries (SIBs) and Na-O batteries is explored. Among these structures, it is proved that only the heterostructures of VS with O-terminated MXenes could load five layers of Na ions, while the others will have a distortion when Na ions intercalate or diffuse in the interlayer or the second adsorption layer. The ultrasmall diffusion barrier of Na ion denotes that these structures have a fast charge/discharge speed, and the ultrasmall open circuit voltages (OCVs) of 0.18 and 0.21 V prove that they are promising candidates for SIBs. The ultralow overpotential 0.55 V/0.20 V for the η/η means that the O facet of the VS/TiCO heterostructure also has a great potential in the application of Na-O batteries. These simulations prove that the heterostructures constructed by TMDs with MXenes have great potential in SIBs and Na-O batteries and are important for future battery design.
钠离子电池因其相似的电化学性质而被视为锂离子电池的替代品，但其容量始终较低。钠-氧电池因其高能量密度而很重要；然而，它们通常受到高过电位的限制。在本论文中，构建了16种不同的过渡金属二卤化物（TMDs）与MXenes（裸表面和氧端基情况）的异质结构，并探索了它们在钠离子电池（SIBs）和钠-氧电池中的应用潜力。在这些结构中，已证明只有VS与氧端基MXenes的异质结构能够负载五层钠离子，而其他结构在钠离子嵌入或扩散到层间或第二吸附层时会发生畸变。钠离子的超小扩散势垒表明这些结构具有快速的充/放电速度，而0.18和0.21 V的超小开路电压（OCVs）证明它们是钠离子电池的有潜力的候选材料。对于η/η的超低过电位0.55 V/0.20 V意味着VS/TiCO异质结构的O面在钠-氧电池的应用中也具有很大潜力。这些模拟证明，由TMDs与MXenes构建的异质结构在钠离子电池和钠-氧电池中具有很大潜力，对未来电池设计具有重要意义。
