Researchers from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) and Yanshan University developed a high-rate anode material for lithium ion battery (LIB). The results were published in Advanced Materials.

Niobium pentoxide (Nb₂O₅) possesses a high specific capacity and fast Li storage kinetics in a safe operating potential window, which is suitable for high-rate battery systems. H-Nb₂O₅ exhibits the highest specific capacity of more than 250 mAh/g (1.0~3.0 V vs Li⁺/Li) among most configurations of Nb₂O₅.

However, the crystal structure of H-Nb₂O₅ would change during Li⁺ (de)intercalation, accompanied with the generation of certain irreversible and inactive phase. That is the main hinderance of H-Nb₂O₅ anodes in practical applications for LIBs.

The scientists in DICP found that optimizing homogeneity of electron and Li-ion transports surrounding the crystals could improve the capacity and cycling life at high rates.

They introduced an amorphous N-doped carbon layer on the micrometer single-crystal H-Nb₂O₅ particle (N-C@MSC-Nb₂O₅) to optimize the homogeneity of phase transition and to suppress the irreversible structure changes.

N-C@MSC-Nb₂O₅ exhibited a long cycling life of over 1000 charge/discharge cycles at a high current density of 2000 mA/g, 10 times longer than that of pristine H-Nb₂O₅.

Moreover, N-C@MSC-Nb₂O₅ also showed a better rate performance than Li₄Ti₅O₁₂-based and other Nb₂O₅-based anode materials. In addition, the inherent principle is further conformed via operando transmission electron microscopy (TEM) and X-ray diffraction (XRD).