Manganese dioxide is considered an ideal cathode candidate material for aqueous zinc-ion batteries. However, its poor conductivity and nanostructural degeneration impede its further application. Herein, a 3 × 3 tunnel-structured τ-MnO₂ cathode material was synthesized through the addition of excessive Mg²⁺. During its preparation, a portion of Mg²⁺ was embedded into the 3 × 3 tunnel of τ-MnO₂ to stabilize the microstructure, while another portion of Mg²⁺ formed a new phase, i.e., Mg₂(OH)₃Cl·4H₂O, adjoining τ-MnO₂, resulting in a cathode material with heterointerface synergy between τ-MnO₂ and Mg₂(OH)₃Cl·4H₂O. The charge arrangement of the heterointerface between τ-MnO₂ and Mg₂(OH)₃Cl·4H₂O enabled more active sites and accelerated ion-diffusion kinetics. The introduction of Mg₂(OH)₃Cl·4H₂O increased the proportion of Mn(IV) and suppressed the structural instability caused by Jahn–Teller distortion, thereby improving the electrochemical performance of the τ-MnO₂ cathode (capacity retention of 86.7% after 1800 cycles at 1 A g⁻¹).

中文翻译：

---

3 × 3 通道 τ-MnO2 阴极与 Mg2（OH）3Cl·4H2O 之间的异质界面协同作用，可实现长循环寿命的水性锌离子电池


二氧化锰被认为是水性锌离子电池的理想阴极候选材料。然而，其较差的导电性和纳米结构退化阻碍了其进一步应用。在此，通过添加过量的 Mg²⁺ 合成了 3 × 3 隧道结构的 τ-MnO₂ 正极材料。在制备过程中，一部分 Mg²⁺ 被嵌入 τ-MnO₂ 的 3 × 3 隧道中以稳定微观结构，而另一部分 Mg²⁺ 形成新的相，即 Mg₂（OH）₃Cl·4H₂O，与 τ-MnO₂ 相邻，得到 τ-MnO₂ 之间具有异质界面协同作用的正极材料和 Mg₂（OH）₃Cl·4H₂O。τ-MnO₂ 和 Mg₂（OH）₃Cl·4H₂O 之间异质界面的电荷排列使更多的活性位点和加速的离子扩散动力学成为可能。Mg₂（OH）₃Cl·4H₂O 的引入增加了 Mn（IV） 的比例，抑制了由 Jahn-Teller 畸变引起的结构不稳定性，从而提高了 τ-MnO₂ 阴极的电化学性能（在 1 A ^g-1 下循环 1800 次后容量保持率为 86.7%）。