Recently, research on ammonium-ion storage has gained widespread interest, and it is still a major problem and a popular research area to produce high-performance electrode materials for aqueous ammonium ion batteries (AAIBs). Herein, the electronic structure of tunnel-like vanadium dioxide (VO₂) is tailored by molybdenum doping (denoted as VO₂-Mo) to enhance ammonium-ion storage properties toward highly efficient AAIBs. VO₂-Mo with a unique nanobelt structure is designed and synthesized by adjusting the content of Mo via a facile hydrothermal method. Density functional theory (DFT) simulations and experimental data both demonstrate that molybdenum atoms in the VO₂ structure can improve mass transfer, speed up ion transport, and accelerate kinetics, showing boosted NH₄⁺-storage properties. With 2% Mo doping, at 0.1 A g⁻¹, VO₂-Mo exhibits a specific discharge capacity of around 370 mA h g⁻¹, surpassing VO₂ (232 mA h g⁻¹) and the vanadium oxide-based materials that have been reported for NH₄⁺-storage. After approximately 6000 successive charging and discharging cycles at 2 A g⁻¹, it essentially maintains the specific capacity of 140 mA h g⁻¹. Using VO₂-Mo, polyaniline (PANI) and 1 M (NH₄)₂SO₄ as the anode, cathode, and electrolyte, respectively, a VO₂-Mo//PANI full battery was further built, and at 0.2 A g⁻¹, it reached a specific discharge capacity of up to 232 mA h g⁻¹, surpassing the performances of the most state-of-the-art AAIBs. At 89 W kg⁻¹, the VO₂-Mo//PANI battery can achieve an energy density (E) up to 133 W h kg⁻¹. This study provides new ideas for tailoring electrode materials with enhanced NH₄⁺-storage for AAIBs.

中文翻译：

---

通过钼掺杂高效水系铵离子电池来定制电子结构以增强 VO2 的铵离子存储性能


近年来，铵离子储存的研究引起了广泛关注，生产用于水系铵离子电池 （AAIB） 的高性能电极材料仍然是一个主要问题和一个热门的研究领域。在此，隧道状二氧化钒 （VO₂） 的电子结构是通过钼掺杂（表示为 VO_2-Mo）定制的，以增强铵离子存储性能，以实现高效的 AAIBs。VO_2-Mo 具有独特的纳米带结构，是通过简单的水热法调节 Mo 的含量来设计和合成的。密度泛函理论 （DFT） 模拟和实验数据都表明，VO₂ 结构中的钼原子可以改善传质、加速离子传输并加速动力学，显示出增强的 NH₄⁺ 存储特性。在 2% Mo 掺杂下，在 0.1 A ^g-1 下，VO_2-Mo 的比放电容量约为 370 mA h ^g-1，超过了 VO₂ （232 mA h ^g-1） 和已报道的用于 NH₄⁺ 存储的氧化钒基材料。在 2 A ^g-1 下连续充电和放电循环大约 6000 次后，它基本上保持了 140 mA h ^g-1 的比容量。 使用 VO_2-Mo、聚苯胺 （PANI） 和 1 M （NH₄）₂SO₄ 分别作为阳极、阴极和电解质，进一步构建了 VO_2-Mo//PANI 满电池，在 0.2 A ^g-1 时，它达到了高达 232 mA h ^g-1 的比放电容量，超过了最先进的 AAIB 的性能。在 89 W ^kg-1 时，VO_2-Mo//PANI 电池可以达到高达 133 W h ^kg-1 的能量密度 （E）。本研究为为 AAIBs 定制具有增强 NH₄⁺ 存储的电极材料提供了新思路。