Ternary Lithium Nickel Boride with 1D Rapid-Ion-Diffusion Channels as an Anode for Use in Lithium-Ion Batteries

Anode materials with high-rate performances and good electrochemical stabilities are urgently required for the grid-scale application of lithium-ion batteries (LIBs). Theoretically, transition metal borides are desirable candidates because of their appropriate working potentials and good conductivities. However, the reported metal borides exhibit poor performances owing to their lack of favorable Li⁺ storage sites and poor structural stabilities during long-term charging/discharging. In this work, a ternary alkali metal boride, Li_1.2Ni_2.5B₂, which displays a high Li⁺ storage capacity and remarkable electrochemical stability and an excellent rate performance is studied. In contrast to conventional transition metal borides, the introduction of Li atoms facilitates the formation of 1D Ni/B-based honeycomb channels during synthesis. This Ni/B framework successfully sustains the strain during Li⁺ intercalation and deintercalation, and thus, the optimized Li_1.2Ni_2.5B₂ anode exhibits an excellent cycle stability over 500 charge/discharge cycles. This electrode also exhibits superior reversible capacities of 350, 183, and 80 mA h g^-1 at 0.1, 1, and 5 A g^-1, respectively, indicating the considerable potential of the 1D Ni/B framework as a commercially available fast-charging LIB anode.