Prediction of Superhard BN2 with High Energy Density
Prediction of Superhard BN2 with High Energy Density
复制标题
高能量密度超硬BN2预测
DOI：
10.1088/0256-307x/38/1/018101
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发表时间：
2021
影响因子：
3.5
通讯作者：
Yinwei Li
中科院分区：
文献类型：
--
作者：
Yiming Zhang;Shuyi Lin;Min Zou;Meixu Liu;Meiling Xu;Pengfei Shen;Jian Hao;Yinwei Li
考虑到在轻元素化合物中压力诱导形成短而强的共价键可以产生超硬材料，我们采用结构搜索和第一性原理计算来预测一类新的氮化硼，其化学计量为BN2，在环境压力下相对于α - b和α - n2稳定。在环境压力下，最稳定的相具有层状结构（h-BN2），其中包含六方BN层，其中有嵌入的N2分子。在25 GPa时，具有单N-N键的三维P42/mmc结构最稳定。动力学、热稳定性和机械稳定性计算表明，这种结构可以在环境条件下恢复。其计算的应力-应变关系表明其具有固有的超硬性质，估计维氏硬度为~ 43 GPa。该结构具有潜在的高能量密度，约4.19 kJ/g。
Considering that pressure-induced formation of short, strong covalent bonds in light-element compounds can produce superhard materials, we employ structure searching and first-principles calculations to predict a new class of boron nitrides with a stoichiometry of BN2, which are stable relative to alpha-B and alpha-N2 at ambient pressure. At ambient pressure, the most stable phase has a layered structure (h-BN2) containing hexagonal BN layers between which there are intercalated N2 molecules. At 25 GPa, a three-dimensional P42/mmc structure with single N–N bonds becomes the most stable. Dynamical, thermal, and mechanical stability calculations reveal that this structure can be recovered under ambient conditions. Its calculated stress-strain relations demonstrate an intrinsic superhard nature with an estimated Vickers hardness of ∼43 GPa. This structure has a potentially high energy density of ∼4.19 kJ/g.