Niu Shifeng, Liu Shijie, Liu Bo, Shi Xuhan, Liu Shuang, Liu Ran, Yao Mingguang, Cui Tian, Liu Bingbing
State Key Laboratory of Superhard Materials, Jilin University Changchun 130012 P. R. China
School of Physics and Engineering, Henan Key Laboratory of Photoelectric Energy Storage Materials and Applications, Henan University of Science and Technology Luoyang 471003 China.
RSC Adv. 2018 Sep 3;8(54):30912-30918. doi: 10.1039/c8ra03453b. eCollection 2018 Aug 30.
Polymeric nitrogen, as a potential high-energy-density material (HEDM), has many applications, such as in energy storage systems, explosives and propellants. Nowadays it is very urgent to find a suitable method to stabilize polymeric nitrogen at ambient conditions. Herein, we present a new hybrid structure where polymeric nitrogen sheets are sandwiched between graphene sheets in the form of a three-dimensional crystal. According to molecular dynamics (AIMD) calculations and phonon spectrum calculations, it is demonstrated that polymeric nitrogen sheets are stable at ambient pressure and temperature. The hybrid material has a higher nitrogen content (the weight ratio of nitrogen is up to 53.84%), and the corresponding energy density is 5.2 kJ g. The hybrid material (A7@graphene system) has a satisfactory energy density, detonation velocity and detonation pressure. Importantly, the hybrid material can be preserved up to 450 K, and above this temperature, the polymeric nitrogen sheets break up into polymeric nitrogen chains or nitrogen gases and release tremendous energy. Further calculations reveal that small charge transfer between the polymeric nitrogen sheets and graphene sheets creates a weak electrostatic attraction compared with other hybrid materials, which is just good for the stabilization of the polymeric nitrogen sheets at ambient conditions, and favors energy release in a gentle way. The proposed confinement hybrid material which has a high energy density and a gentle energy release temperature, provides a highly promising method for the capture and application of polymeric nitrogen in a controllable way.
作为一种潜在的高能量密度材料（HEDM），聚合氮有许多应用，例如在储能系统、炸药和推进剂中。如今，迫切需要找到一种合适的方法在环境条件下稳定聚合氮。在此，我们提出一种新的混合结构，其中聚合氮片以三维晶体的形式夹在石墨烯片之间。根据分子动力学（AIMD）计算和声子谱计算，结果表明聚合氮片在常压和常温下是稳定的。这种混合材料具有较高的氮含量（氮的重量比高达53.84%），相应的能量密度为5.2 kJ/g。该混合材料（A7@石墨烯体系）具有令人满意的能量密度、爆速和爆压。重要的是，这种混合材料在高达450 K的温度下都能保持稳定，高于此温度时，聚合氮片会分解成聚合氮链或氮气并释放出巨大能量。进一步的计算表明，与其他混合材料相比，聚合氮片和石墨烯片之间的小电荷转移产生了较弱的静电吸引力，这恰好有利于在环境条件下稳定聚合氮片，并有利于以温和的方式释放能量。所提出的受限混合材料具有高能量密度和温和的能量释放温度，为以可控方式捕获和应用聚合氮提供了一种极具前景的方法。
