Although spinel ZnMn₂O₄ (ZMO) has been regarded as a potential cathode material for aqueous zinc-ion batteries (ZIBs), the unsatisfactory long-term cycling stability seriously restricts its commercial applications. To overcome this obstacle, it is urgent to clarify the energy storage mechanism and cycling degradation reason of spinel ZMO upon Zn²⁺ insertion/extraction. Herein, the phase and structure evolutions of spinel ZMO are deeply probed by means of in-situ and ex-situ investigations, which is closely related to the reversible phase transformation between spinel ZMO and MnO₂ during charging-discharging, while irreversible formation of inactive ZnO byproduct could cause the capacity fading after repeated cycles. Guided by the clear electrochemical mechanism, a 3D assembly of Ti-MXene (Ti₃C₂T_x)-stabilized ZMO nanoparticles has been designed and synthesized, in which high-conductive Ti₃C₂T_x scaffold can effectively inhibit the irreversible structural degradation and side reaction of spinel ZMO. As a result, the ZMO@Ti₃C₂T_x composite cathode exhibits a large reversible specific capacity, excellent rate capability and long-term cyclic stability (capacity retention of ~92.4% after 5000 cycles), superior than previously reported ZMO-based cathodes in aqueous ZIBs. For real applications, a kind of flexible aqueous ZIBs are fabricated and represent stable electrochemical performance at various deformation states, indicating their potential applications in portable/wearable electronics.

尽管尖晶石ZnMn ₂ O ₄（ZMO）被认为是水性锌离子电池（ZIBs）的潜在阴极材料，但令人满意的长期循环稳定性严重限制了其商业应用。为了克服这一障碍，迫切需要弄清楚尖晶石ZMO在Zn ^2+的插入/抽出过程中的储能机理和循环降解的原因。此处，尖晶石ZMO的相位和结构演变借助于进行了深入探讨的原位和易地调查，其中密切相关尖晶石ZMO和MnO之间的可逆相变₂在充放电过程中，不可逆的ZnO副产物的不可逆形成可能导致重复循环后容量衰减。在明确的电化学机理的指导下，设计合成了Ti-MXene（Ti ₃ C ₂ T _x）稳定的ZMO纳米粒子的3D组装体，其中高导电Ti ₃ C ₂ T _x支架可以有效抑制不可逆结构尖晶石ZMO的降解和副反应。结果，ZMO @ Ti ₃ C ₂ T _x复合阴极具有大的可逆比容量，优异的倍率能力和长期循环稳定性（5000次循环后容量保持率约为92.4％），优于先前报道的ZIB水溶液中的ZMO基阴极。对于实际应用，制造了一种柔性水性ZIB，它们在各种变形状态下表现出稳定的电化学性能，表明它们在便携式/可穿戴电子产品中的潜在应用。