Rational design towards Zn-based anode for dendrite-free and durable alkaline Ni-Zn batteries

Alkaline Ni-Zn batteries have gained great scientific and industrial interest. However, Zn-based anodes still suffer from serious challenges, mainly including Zn dendrites, hydrogen evolution reaction (HER), corrosion, deformation, and passivation. Herein, an effective strategy is proposed to overcome/alleviate these challenges: First, micron-sized ZnO with spherical structure that can minimize the property difference induced by anisotropy and the surface area exposed to the alkaline electrolyte is prepared as active materials; Second, Ga is introduced into the matrix of ZnO to increase the initial conductivity; Third, thin carbon layer is coated onto the ZnO to further enhance the conductivity and prevent its direct contact with the severe electrolyte. The optimal material of carbon coated Ga-doping ZnO (GZO@C) can deliver a rather high capacity of ∼ 632 mAh g-1 (charged with a theoretical value of 659 mAh g-1, 100 % depth of discharge), reflecting low proportion of HER concerned side reactions. The capacity is well maintained for about 1300 cycles at 4.0 A g-1. There is no obvious capacity decay along with the increase of charge/discharge current, indicating good rate performance. Morphology change of the active materials is also restrained, suggesting the avoidance of Zn dendrites and deformation.