全钒液流电池电极材料关键问题及应对策略

Key issues and corresponding strategies of electrode for vanadium redox flow battery

摘要:

全钒液流电池（VRFB）凭借长寿命、安全、环保以及容量规模可扩展等特性，成为未来极具前途的大规模储能系统之一。电极作为VRFB核心部件，对电池能量效率有着重大影响。但电极催化面积不足、催化活性低、长循环过程中老化损耗、存在析氢副反应等缺点阻碍了VRFB进一步商业化。电极老化和析氢副反应（HER）会减少VRFB使用寿命，降低VRFB性能。对于电极老化以及HER的问题缺少可靠的应对策略，急需对已有研究成果进行归纳总结。该文综述了提高电极催化面积及催化活性策略；详细讨论了电极老化特征、老化监测方法、HER的影响因素以及HER先进表征技术；最后，结合研究现状为VRFB电极材料未来的发展提出了切实可行的建议：加固碳纤维以及增强电极中sp2碳稳定性将是延缓电极老化的重要策略，金属和金属氧化物催化剂以及更均匀的电极材料则具有抑制HER的巨大潜力。

Abstract:

Vanadium redox flow battery (VRFB) is regarded as one of the most promising massive electricity storage systems, because of its long cyclic life, good safety, environmentally friendly structure and flexible design. As one of the core components of VRFB, the electrode has a significant impact on the energy efficiency of the battery. However, the inherent shortcomings of the electrode have hindered the further commercial application of VRFB, including insufficient catalytic area, poor catalytic activity, the degradation of electrode, hydrogen evolution side reaction (HER) and so on. Electrode aging and HER can reduce the lifespan of VRFBs and degrade their performance. There is a lack of reliable strategies to address these issues, necessitating a comprehensive summary and synthesis of existing research findings. This paper reviews strategies for enhancing electrode catalytic area and catalytic activity; thoroughly discusses the characteristics of electrode aging, methods for monitoring electrode aging, factors influencing HER, as well as advanced characterization techniques for HER; finally, practical and feasible suggestions for the future development of VRFB electrode materials are proposed based on the current research status：the reinforcement of carbon fiber and the enhancement of sp2 carbon stability within electrodes will be key strategies for retarding electrode aging. Metal and metal oxides, as well as more uniform electrode materials, hold great potential in suppressing HER.