Ultrahigh energy density Li-ion batteries based on cathodes of 1D metals with -Li-N-B-N- repeating units in alpha-LixBN2 (1 %26lt;= x %26lt;= 3)

作者：Nemeth Karoly^*

来源：Journal of Chemical Physics, 2014, 141(5): 054711.

DOI：10.1063/1.4891868

Ultrahigh energy density batteries based on alpha-LixBN2 (1 %26lt;= x %26lt;= 3) positive electrode materials are predicted using density functional theory calculations. The utilization of the reversible LiBN2 + 2 Li+ + 2 e(-) reversible arrow Li3BN2 electrochemical cell reaction leads to a voltage of 3.62V (vs Li/Li+), theoretical energy densities of 3251 Wh/kg and 5927 Wh/l, with capacities of 899 mAh/g and 1638 mAh/cm(3), while the cell volume of alpha-Li3BN2 shrinks only 2.8% per two-electron transfer on charge. These values are far superior to the best existing or theoretically designed intercalation or conversion-based positive electrode materials. For comparison, the theoretical energy density of a Li-O-2/peroxide battery is 3450 Wh/kg (including the weight of O-2), that of a Li-S battery is 2600 Wh/kg, that of Li3Cr(BO3)(PO4) (one of the best designer intercalation materials) is 1700 Wh/kg, while already commercialized LiCoO2 allows for 568 Wh/kg. alpha-Li3BN2 is also known as a good Li-ion conductor with experimentally observed 3 mS/cm ionic conductivity and 78 kJ/mol (approximate to 0.8 eV) activation energy of conduction. The attractive features of alpha-LixBN2 (1 %26lt;= x %26lt;= 3) are based on a crystal lattice of 1D conjugated polymers with -Li-N-B-N- repeating units. When some of the Li is deintercalated from alpha-Li3BN2 the crystal becomes a metallic electron conductor, based on the underlying 1D conjugated pi electron system. Thus, alpha-LixBN2 (1 %26lt;= x %26lt;= 3) represents a new type of 1D conjugated polymers with significant potential for energy storage and other applications.

• 出版日期2014-8-7