Process engineering in electrochemical energy devices innovation

This review focuses on the application of process engineering in electrochemical energy conversion and storage devices innovation. For polymer electrolyte based devices, it highlights that a strategic simple switch from proton exchange membranes(PEMs) to hydroxide exchange membranes(HEMs) may lead to a new-generation of affordable electrochemical energy devices including fuel cells, electrolyzers, and solar hydrogen generators. For lithium-ion batteries, a series of advancements in design and chemistry are required for electric vehicle and energy storage applications. Manufacturing process development and optimization of the LiF eP O_4/C cathode materials and several emerging novel anode materials are also discussed using the authors' work as examples.Design and manufacturing process of lithium-ion battery electrodes are introduced in detail, and modeling and optimization of large-scale lithium-ion batteries are also presented. Electrochemical energy materials and device innovations can be further prompted by better understanding of the fundamental transport phenomena involved in unit operations.

Ordered Nafion ionomers decorated polypyrrole nanowires for advanced electrochemical applications

Fabrication of novel electrode materials with ordered proton-migration channels is an effective strategy to enhance the proton conductivity of the electrode for polymer electrolyte membrane fuel cells. Here we report the electrochemical fabrication of ordered Nafion？ionomers decorated polypyrrole nanowires to construct the ordered proton-migration channels. Based on the electrostatic interaction between Nafion？ionomers and the polymer intermediate, ordered Nafion？ionomers decorated polypyrrole nanowires could be fabricated via chronoamperometry with varying contents of Nafionionomers. The morphologies, charge-storage performances, electron conductivity and proton conductivity of the composites are investigated by scanning electron microscopy, cyclic-voltammetry, galvanostatic charge–discharge measurement and electrochemical impedance spectroscopy. With the modification effect of Nafionionomers on polypyrrole nanowires, the composite shows greater ordered structure relative to another without Nafion？ionomers and the electrochemical performances change with the content of Nafion？ionomers.The composite could achieve a high specific capacitance of 356 F/g at 1 A/g with a 0.62-fold enhancement compared to polypyrrole nanowires without Nafion？ionomers. It also displays a superior electrical conductivity of 49 S/cm and a quite high proton conductivity of 0.014 S/cm at working conditions of fuel cells, which are associated with the requirements of fuel cells and have the potential to be the electrode material for a large range of electrochemical energy conversion devices.