An effective Ni(OH) 2 optimization strategy via Cu 2+ and Ni 3+ co-doping for high capacity and long life-span lithium ion batteries

Although novel anode materials made of transition metal hydroxide can initially exhibit high capacity, their cycling performances would rapidly decline due to the poor structural stability and low electrical conductivity. Herein, we demonstrated a novel design strategy to prepare a Cu2+ and Ni3+ co-doped nickel-based layered double hydroxide (LDH) by a simple one-step co-precipitation method. The well-doped Cu2+ shortens the band gap and enhances the interlamellar spacing of the co-doped LDH, thus promoting the migration of electrons and lithium ions, and increasing the stability of layered structure. Moreover, in situ generated Ni3+ not only shorten the overall band gap but also improve the pseudocapacitance of the Ni-based LDH material. As a result, the co-doped nickel-based LDH exhibit an ultra-high capacity of 942.5 mAh g−1 after 1000 cycles under the rate of 2 A g−1, which behaves outstanding cycling performance in comparison with all the reported nickel-based hydroxide anode materials to our knowledge. In addition, the reversible discharge capacity at 1 A g−1 of the co-doped nickel-based layered double hydroxide anode at a low voltage window (0.01~1.5 V) is more than four times of that of the common Ni(OH)2 anode after 800 cycles.