Built defects of homogeneous junction to enhance the lithium storage capacity of niobium pentoxide materials

Abstract

Niobium pentoxide (Nb2O5) is deemed one of the promising anode materials for lithium-ion batteries (LIBs) for its outstanding intrinsic fast Li-(de) intercalation kinetics. The specific capacity, however, is still limited, because the (de) intercalation of excessive Li-ions brings the undesired stress to damage Nb2O5 crystals. To increase the capacity of Nb2O5 and alleviate the lattice distortion caused by stress, numerous homogeneous H- and M- phases junction interfaces were proposed to produce coercive stress within the Nb2O5 crystals. Such interfaces bring about rich oxygen vacancies with structural shrinkage tendency, which pre-generate coercive stress to resist the expansion stress caused by excessive Li-ions intercalation. Therefore, the synthesized Nb2O5 achieves the highest lithium storage capacity of 315 mA h g−1 to date, and exhibits high-rate performance (118 mA h g−1 at 20 C) as well as excellent cycling stability (138 mA h g−1 at 10 C after 600 cycles).