Mesoporous Ti4O7 Spheres with Enhanced Zinc-Anchoring Effect for High-Performance Zinc-Nickel Batteries.

Abstract

Zinc-nickel batteries are promising competitors for next-generation power supply due to their benefits of high safety, high working voltage, and attractive rate performance. However, their practical applications are plagued by their poor cycling performance, stemming from uneven redistribution of zinc during cycling that results in dendrite formation and shape changes of the electrode. In this work, mesoporous Ti4O7 microspheres are prepared and are employed as additives of a zinc anode. Notably, the presence of mesopores provides abundant chemisorption sites for Zn(OH)42- ions, inhibiting severe zinc redistribution in the electrode. Moreover, due to the good electrical conductivity and mesopores that serve as ion diffusion channels, the reaction reactivity and reversibility of the zinc electrode are greatly facilitated. As a result, the fabricated zinc-nickel battery with mesoporous Ti4O7 additives (ms-Ti4O7) exhibits an enhanced discharge capacity and a significantly prolonged cycling life. Even at a current of 10 A (∼138 mA cm-2), the ms-Ti4O7-modified anode demonstrates stable operation for longer than 718 h (700 cycles) with a discharge voltage of 1.2 V, which is much longer than those of a ZnO anode (192 h, 117 cycles) and a Ti4O7-particle (p-Ti4O7)-modified battery (590 h, 443 cycles). Furthermore, due to the anchoring effect for Zn(OH)42- and the uniform electric field, the effect of mesoporous Ti4O7 on inhibiting dendrite formation and shape change of the zinc electrode is highlighted.