Synthesis and electrochemical properties of calcium cobaltate as novel anode material
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Synthesis and electrochemical properties of calcium cobaltate as novel anode material Xiao Chen1 · Shiyun Zhou2 · Chuanqi Feng1 Received: 29 February 2020 / Accepted: 3 August 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract The calcium cobaltate (Ca3Co4O9) is synthesized through rheological phase reaction method using calcium gluconate (Ca(C6H12O6)2), citric acid (C6H8O7) and cobalt acetate tetrahydrate (CoAc2·4H2O) as raw materials. The germanium dioxide (GeO2) and bismuth nitrate pentahydrate (Bi ( NO3)3·5 H2O) or both of them are used as precursors to synthesize Ge and Bi cation-doped calcium cobaltate ( Ca3Co4O9) to improve its electrochemical properties. At first, the precursors were formed at 120 °C for 12 h using rheological phase mixtures of designed raw materials. Then, precursors were heated at different temperatures to obtain calcium cobaltate ( Ca3Co4O9) samples. Because of doping of G e4+ or B i3+ or both of them, the conductivity and electrochemical performances for Ca3Co4O9 could be improved to a certain degree. The electrochemical tests showed that its electrochemical performances are depended on its calcination temperature and different kinds of doping. When calcined temperature was set at 750 °C, sample doped by both Ge4+ and Bi3+ (such as designed expected compound Ca2.85Bi0.15Co3.85Ge0.15O9) exhibited high reversible capacity at current density of 100 mAg−1 in voltage range of 0.01–3.0 V, and its reversible capacity could maintain at 550 mAhg−1 after 50 cycles. The reasons for Ca2.85Ge0.15Co3.85Bi0.15O9 to exhibit outstanding electrochemical properties were discussed also. The calcium cobaltate ( Ca3Co4O9) doped by both G e4+ and B i3+ is a promising anode material for lithium ion battery application.
1 Introduction Cobalt oxide ( Co3O4) has been widely studied as a very promising anode material because of its high reversibility and ease for preparation when compared with other cobalt oxides/nitrides (such as CoO, Co2O3 and CoN) [1, 2]. However, Co metal is expensive and toxic element. Therefore, it is worthwhile to partially replace the Co in the Co3O4 with a cheaper and more environmental friendly alternative elements without sacrificing its electrochemical performance. As a result, some spinel compounds M xCo3−xO4 * Shiyun Zhou [email protected] * Chuanqi Feng [email protected] 1
Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Ministry‑of‑Education Key Laboratory for Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan, People’s Republic of China
School of Electronic and Information Engineering, Anshun University, Anshun, People’s Republic of China
2
(M=Ni [3, 4], Mn [5], Fe [6], Cu [7], Zn [8], etc.) having the same structural properties as those of C o3O4 were synthesized, and these compounds can be made to reversibly react with lithium mainly by a conversion reaction with a possible alloy/dealloying reaction. The ZnxCo3−xO4 as electrode belongs to this
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