储能科学与技术

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质子电池负极材料W掺杂α-MoO3 的制备和研究

马晓锋1,2(), 邵钦君1, 陈剑1()   

  1. 1.中国科学院大连化学物理研究所，辽宁 大连 116023
    2.中国科学院大学，北京 100049
  • 收稿日期:2024-03-20 修回日期:2024-04-01
  • 通讯作者: 陈剑 E-mail:maxf@dicp.ac.cn;chenjian@dicp.ac.cn
  • 作者简介:马晓锋（1998—），男，硕士研究生，研究方向为质子电池负极材料，E-mail：maxf@dicp.ac.cn；
  • 基金资助:
    国家科技计划项目(BX221C012)

Preparation and research of W-doped α-MoO3 as anode materials for proton battery

Xiaofeng MA1,2(), Qingjun SHAO1, Jian Chen1()   

  1. 1.Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
  • Received:2024-03-20 Revised:2024-04-01
  • Contact: Jian Chen E-mail:maxf@dicp.ac.cn;chenjian@dicp.ac.cn

摘要：

质子带有一个正电荷，具有最小的离子半径和最轻的质量；并且氢元素在地球上的丰度较高，可充电的质子电池有望成为下一代新型储能二次电池。目前，常被用作质子电池负极材料的有α-MoO3、WO3、TiO2和MXenes等，尚存在放电比容量低、倍率性能差等问题。α-MoO3是一种层内由［MoO6］八面体双亚层组成、层与层之间通过范德华力相连接的层状晶体化合物，3电子反应对应较高的理论比容量558 mAh·g-1，且嵌脱质子的电极电势较低，是最有应用前景的质子电池负极材料之一。但是，在水系电解液中，当电池放电时，水合质子在α-MoO3表面脱溶剂化可导致材料的晶格扭曲和坍塌，造成材料的可逆容量衰减。本工作首次合成了W掺杂的α-MoO3材料。XRD和RAMAN结果显示，掺杂的W进入化合物的Mo位点形成了键能更高的W-O键，并增强了层间的Mo=O键。并且，W6+的离子半径为0.60 ?，较Mo6+的0.59 ?更大，W掺杂材料的层间距从未掺杂时的13.84 ?增大到掺杂后的13.87 ?。电化学研究结果显示，质子嵌入W掺杂的α-MoO3的反应动力学得到明显提升，电极反应从由质子在材料中的固相扩散传质控制转变为由电极表面的转化反应控制为主。α-MoO3和W0.035Mo0.965O3材料分别以5 C（1 A·g-1）倍率进行充放电，可逆比容量分别为202.4 mAh·g-1和189.2 mAh·g-1。充放电循环600圈后，W0.035Mo0.965O3的容量保持率为83.0%，而α-MoO3的仅为69.6%。当放电倍率提高至125 C（25 A·g-1）时，W0.035Mo0.965O3材料仍表现出144.2 mAh·g-1的放电比容量，而α-MoO3的放电比容量仅为90.7 mAh·g-1。最后，本工作以MnO2为正极、W0.035Mo0.965O3为负极、玻璃纤维纸为隔膜、2 mol·L-1 H2SO4 + 1 mol·L-1 MnSO4为电解液组装了全电池。该电池以15 C倍率（3 A·g-1）放电的可逆比容量为177.0 mAh·g-1，循环400圈后的容量保持率为83.8%。研究结果表明，W掺杂有效提高了α-MoO3材料的稳定性和倍率性能。

关键词: 质子电池, α-MoO3, 钨掺杂

Abstract:

Proton carries one positive charge with the smallest ionic radius and lightest mass. Meanwhile, element hydrogen is ubiquitous on Earth that makes rechargeable proton battery systems become the next generation of energy storage battery. To date, anode materials for proton batteries, such as WO3, TiO2 and MXenes, still suffer from low discharge capacity and poor rate performance. α-MoO3 is one of the layered crystalline compounds composed of [MoO]6 octahedra double sublayers which are connected by van der Waals interaction. α-MoO3 possess high theoretical specific capacity of 558 mAh·g-1 due to 3 electron reaction, and low proton insertion potenetial which is recognized one of the most promising anode materials for proton batteries. Unfortunately, α-MoO3 suffers severe lattice distortion and damage in aqueous electrolytes during discharge process, causing the rapid decay of the reversible capacity. In this work, we reports the synthesis of W-doped α-MoO3 for the first time. The XRD and RAMAN results show that the substitution of Mo with W formed stronger W-O bond and enhanced the inlayer Mo=O bond. In addition, the interlayer spacing of α-MoO3 increases from 13.84 ? to 13.87 ? after W-doped because that the W6+ has a larger radius (0.60 ?) than Mo6+(0.59 ?). Moreover, the CV results show that the redox reactions of the W-doped material are mainly controlled by charge transfer of the electrode surface atoms rather than proton diffusion mass transfer in materials. The reversible discharge capacities of the α-MoO3 and W0.035Mo0.965O3 are 202.4 mAh·g-1 and 189.2 mAh·g-1 at 5 C (1 A·g-1). After 600 cycles, the capacity retention is 83.0% for W0.035Mo0.965O3, which is higher than that of α-MoO3 (69.6%). Even at 125 C (25 A·g-1), W0.035Mo0.965O3 still deliver a discharge capacity of 144.2 mAh·g-1 which is higher than α-MoO3 (90.7 mAh·g-1) . Subsequently, the full cell in Swagelok cell was assembled using MnO2 as the cathode, W0.035Mo0.965O3 as the anode, glass fiber filter paper as the separator, and 2 mol·L-1 H2SO4 + 1 mol·L-1 MnSO4 as the electrolyte. At 15 C (3 A·g-1), the full cell exhibits a reversible capacity of 177.0 mAh·g-1 and a capacity retention of 83.8% after 400 cycles. These results show that W doping could effectively improve the cycling stability and rate performance of α-MoO3 materials.

Key words: aqueous proton battery, α-MoO3, tungsten doping

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