Directly grown nanostructured electrodes for high-power and high-stability alkaline nickel/bismuth batteries

Bismuth oxide (Bi ₂ O ₃ ) has received great attention as an anode material for alkaline nickel/bismuth (Ni/Bi) batteries due to its high theoretical capacity and easy preparation. However, the generally poor conductivity of metal oxides and the instability of Bi ₂ O ₃ during cycling severely limit the device performance. Herein, we present the use of directly grown Bi ₂ O ₃ nanoflake film with kinetic advantages as the anode for Ni/Bi batteries. Particularly, glucose-derived carbon is integrated onto the surfaces of nanoflakes, which not only enhances the electron transfer but also buffers the conversion-reaction induced volume expansion of Bi ₂ O ₃ , helping maintaining the cycling stability of the film. The resulting Bi ₂ O ₃ @C electrode exhibits high specific capacity, excellent rate performance (can be charged within 6.7 s), and good cycle stability (∼1,200 times; fading rate of only 0.011% per cycle). When assembled with a nickel oxide (NiO) nanosheet array cathode in basic electrolyte, a fully binder-free Ni/Bi battery is obtained, which delivers maximum energy and power densities of 34.29 W h kg ⁻¹ and 12,159.8 W kg ⁻¹ , respectively, and good cycling performance. The power density is even much superior to that of many hybrid/asymmetric supercapacitors. Our work suggests a new generation of thin-film Ni/Bi batteries for potential high-power electronic applications. © 2018, Science China Press and Springer-Verlag GmbH Germany, part of Springer Nature.