All-Vanadium Redox Flow Battery Stack and Key Technologies

This document provides a comprehensive overview of all-vanadium redox flow battery (VRFB) stacks and their key technologies. It begins with the background of flow batteries, highlighting China's rapid growth in new energy storage, with cumulative installed capacity reaching 892 MW / 3554 MWh in 2024. The intrinsic safety, long cycle life, low full lifecycle cost, and independent controllability of vanadium resources are emphasized. The principle and structure of VRFB stacks are explained, including the positive and negative electrode reactions and stack components such as end plates, bipolar plates, electrodes, and membranes. Core components—electrolyte, electrode, ion exchange membrane, electrode frame, and bipolar plates—are analyzed, along with existing issues like high electrolyte cost, low vanadium solubility, and difficulty in mass-producing high-performance electrodes. The document discusses bipolar plate materials (carbon-plastic composites, flexible and rigid graphite) and electrode materials (graphite felt, carbon cloth, carbon paper) with activation methods including intrinsic treatment and catalyst introduction. Key challenges such as electrochemical, concentration, and ohmic polarization are identified, and strategies to reduce levelized cost of energy through high power density stacks, low-cost materials, and efficient sealing are proposed.