论文标题
高压过渡金属阴极材料Libc3f4用于李离子电池
High voltage transition metal-free cathode material LiBC3F4 for Li ion batteries
论文作者
论文摘要
通过第一原理计算，研究了硼取代的氟化石墨的结构稳定性和电化学性能。结果表明，硼取代的氟化石墨BC3F4具有出色的结构稳定性，良好的电和离子电导率。出乎意料的是，LIBC3F4的平均LI插入电压高达4.44 V，比LIBCF2大得多。 LIBC3F4的平均电压甚至比普通的商业过渡金属氧化物阴极的平均电压大，这表明LIBC3F4是过渡金属无金属高压阴极材料的突破。通过比较费米水平，我们发现LIBC3F4的费米水平比LiBCF2低1.38 eV，从而导致电子填充能量减少LI插入并形成更高的电压。此外，libc3f4显示出较小的体积膨胀和高能量密度。 LIBC3F4是一种有前途的高压阴极材料，用于李离子电池。最后，通过计算放电过程中LI插入电压和费米水平的演变，已经发现了费米水平与LI插入电压之间的线性相关性。
The structural stability and electrochemical performance of boron substituted fluorinated graphite as a Li ion batteries cathode material are studied by first principles calculations. The results show that boron substituted fluorinated graphite BC3F4 possesses excellent structural stability, good electrical and ionic conductivities. Unexpectedly, the average Li intercalation voltage of LiBC3F4 is up to 4.44 V, which is much larger than that of LiBCF2. The average voltage of LiBC3F4 is even larger than that of common commercial transition metal oxides cathodes, indicating that LiBC3F4 is a breakthrough of transition metal-free high voltage cathode materials. By comparing the Fermi level, we found the Fermi level of LiBC3F4 is 1.38 eV lower than that of LiBCF2, leading to the decrease of the electron filling energy for the Li intercalation and forming much higher voltage. Moreover, LiBC3F4 shows small volume expansion and high energy density. LiBC3F4 is a promising high voltage cathode material for Li ion batteries. Finally, by calculating the evolution of Li intercalation voltage and Fermi level during the discharging process, a linear correlation between the Fermi level and Li intercalation voltage has been found.
