Surfacing Amorphous Ni-B Nanoflakes on NiCo2O4 Nanospheres as Multifunctional Bridges for Promoting Lithium Storage Behaviors
Transition metal oxides (TMO) have gained enormous research interests as the negative materials of next generation lithium-ion batteries due to their higher energy density, lower cost and better eco-friendliness. However, they are subjected to low electronic conductivities and dramatic volume change during charge/discharge and there is also great challenge to realize the TMO electrodes with satisfactory LIB performances. In this work, amorphous nickel-boride (Ni-B) was introduced into porous NiCo2O4 nanospheres by an in situ solution growth route for the first time, to overcome the existed issues. The coated Ni-B component could not only function as anchors for NiCo2O4 nanospheres to suppress the severe volume expansion, but also act as effective electron-conducting bridges to promote fast electron/charge transfer. Furthermore, the existence of abundant of mesopores centered at ~6.5 nm in this composite could effectively suppress the severe volume variations in the lithiation/delithiation process. As expected, the NiCo2O4@Ni-B composites delivered a high reversible capacity of 1221 mAh g−1 at 0.2 A g−1, and 865 mAh g−1 at 0.5 A g−1 over 500 cycles; more impressively, at high rate of 5 A g−1, a capacity of 648 mAh g−1 could be also obtained, showing its good rate capability. As a result, these results demonstrated an effective and facile way to design conversion-type negative electrode materials with superior lithium storage properties.