Lithium storage mechanism in superior high capacity copper nitrate hydrate anode material

Copper nitrate hydrate (Cu(NO 3 ) 2 ·2.5H 2 O) exhibits superior high lithium storage capacity (2285 mAh g −1 ) as anode material for lithium-ion batteries. The structural transformation and lithium storage mechanism of Cu(NO 3 ) 2 ·2.5H 2 O are thoroughly studied by various advanced analytical techniques. It is found that the lithium storage process of Cu(NO 3 ) 2 ·2.5H 2 O is associated with a quasi-reversible electrochemical conversion reaction. During the discharge process, the electrochemical reaction of Cu(NO 3 ) 2 ·2.5H 2 O with lithium results in the formation of Cu, LiNO 3 , Li 3 N, Li 2 O and H 2 O. In the reverse charge process, Cu(NO 3 ) 2 can be generated by a conversion reaction. As a result, Cu(NO 3 ) 2 ·2.5H 2 O shows the reversible charge capacities of 1632.1 mAh g −1 in 0.0–3.4 V and 689.1 mAh g −1 in 1.0–3.4 V, respectively.