Interface‐Engineered Strategy on Carbon Nanotubes to Chemical Stabilize Graphene as a Self‐Healing Fiber Electrode for Superior Capacitive Deionization

Nanocomposite technology is an effective strategy to enhance the performance of capacitive deionization (CDI). However, the poor interfacial interactions between the nanofillers and matrices limit their further optimization and commercial application. Here, we developed an interface engineering strategy to prepare a high‐strength and high‐toughness fiber electrode based on holey reduced graphene oxide (HRGO) and carboxylated carbon nanotubes (CCNT) through introducing borate bonds as bridging interactions. The interface interaction between HRGO and CCNT is significantly enhanced by the formation of dynamic cross‐linked borate bonds, which not only effectively prevent π‐π stacking and construct hierarchical ion transport channels to enhance ion transport efficiency and reaction kinetics, but also significantly improve mechanical stability and long‐cycle performance based on self‐healing properties in the fiber electrode. This configuration showed remarkably enhanced desalination capacity (30.6 mg g −1 ) and higher desalination rate (6.12 mg g −1 min −1 ), with cycling performance exceeding 90%, which exceeds previously reported values. Density functional theory calculations further reveal the mechanism by which the nanocomposite interface affects the CDI performance. Based on this excellent performance, we established a recirculating desalination hydrogen production system consisting of multiple CDI units connected in series with a hydrogen production unit. This effective strategy opens a new way to optimize the nanocomposite interfaces and achieve efficient electrochemical reactions.