Enhanced sodium storage property of copper nitrate hydrate by carbon nanotube

In this work, novel nano/micro structure nitrates are reported for sodium storage for the first time. By using a facile solution route, carbon black (CB) and carbon nanotube (CNT) are introduced to incorporate with copper nitrate hydrate (Cu(NO3)(2)center dot 2.5H(2)O) to form Cu(NO3)(2)center dot 2.5H(2)O/CB and Cu(NO3)(2)center dot 2.5H(2)O/NT composites for high capacity sodium storage, respectively. Morphological and structural investigations show that CB or CNT coating does not obviously change the particle size and phase composition of Cu(NO3)(2)center dot 2.5H(2)O, while, the electrochemical performance of Cu(NO3)(2)center dot 2.5H(2)O is significantly improved by introducing CB or CNT as a conductive network. Moreover, carbon matrix can also provide a buffer for suppressing particle pulverization during sodiation/desodiation process. Especially for CNT, it builds a three-dimensional conductive network for active particles. As a result, Cu(NO3)(2)center dot 2.5H(2)O/CNT exhibits higher reversible specific capacity and better cycling stability than bare Cu(NO3)(2)center dot 2.5H(2)O and Cu(NO3)(2)center dot 2.5H(2)O/CB. After 30 cycles, Cu(NO3)(2)center dot 2.5H(2)O/CNT can deliver a reversible charge capacity of 140.7 mAh g(-1) at a current density of 50 mA g(-1). This result demonstrates that CNT reinforced Cu(NO3)(2)center dot 2.5H(2)O composite could be a probable anode material for sodium-ion batteries. Besides, the probable sodium storage mechanism in Cu(NO3)(2)center dot 2.5H(2)O is also proposed by using various ex-situ analytical methods. (C) 2015 Elsevier B.V. All rights reserved.