Mesoporous orthorhombic Nb2O5 nanofibers as pseudocapacitive electrodes with ultra-stable Li storage characteristics

Abstract

Ultra-stable pseudocapacitive electrodes for lithium-ion batteries (LIBs) are increasing in demand as highly sustainable energy storage system with excellent charge transport is important. The establishment of facile, controllable, and scalable synthesis of pseudocapacitive electrode materials is an attractive solution to realize such objectives. Here, we have successfully fabricated mesoporous orthorhombic Nb2O5 nanofibers (m-T-Nb2O5 NFs) by simple single-spinneret electrospinning followed by calcination at 600 degrees C. As-formed m-T-Nb2O5 NFs exhibit high surface area (23.7 m(2) g(-1)) and a number of mesopores in the vacant sites where organic polymer was once decomposed. Such rationally designed m-T-Nb2O5-NFs allow facile Li ion and electron transport, with pseudocapacitive behavior. Arising from the high surface area coupled with mesopores in-between the Nb2O5 nanograins, it exhibits ultra-long cycle retention (a capacity of similar to 160 mAh g(-1) at 500 mA g(-1) after 2000 cycles and similar to 88 mAh g(-1) at 3000 mA g(-1) after 5000 cycles) and higher rate capability (similar to 70 mAh g-1 at 5000 mA g(-1)). Such cycle retention characteristics of m-T-Nb2O5-NFs are at least 100-fold slower capacity decay compared with previously reported one-dimensional (1D) Nb2O5 nanostructures and even superior or comparable to recently reported Nb2O5-graphene composite materials.