Okay, I need to create a Wikipedia-style document about FCEVs (Fuel Cell Electric Vehicles) under the categories of Technology → Automotive → Electric Vehicles. Let me start by understanding what an FCEV is. From what I remember, FCEVs use hydrogen fuel cells to generate electricity, which powers the motor. They're different from battery electric vehicles (BEVs) because they produce electricity on board using hydrogen.

First, the structure: H1 for the title, then an overview section. Then sections with H2 and H3 headings. I need to make sure each part is detailed but clear. Let me think about the key points to cover.

The introduction should explain what FCEVs are, their basic working principle, and maybe a brief history. Then, technical aspects like fuel cell systems, hydrogen storage, and powertrain components. Comparing them with BEVs would be useful. Also, current market status, challenges, and future prospects.

I need to check if I have all the necessary information. For example, how do fuel cells work? They convert hydrogen and oxygen into electricity, water, and heat. The main components are the stack, hydrogen tank, electric motor, and control systems. Safety is a concern with high-pressure tanks, so that's worth mentioning.

Challenges include hydrogen production (most from fossil fuels), infrastructure for refueling stations, cost of fuel cells, and efficiency compared to BEVs. On the other hand, FCEVs have longer ranges and faster refueling times than BEVs, which are advantages.

I should also mention some examples like Toyota Mirai, Hyundai Nexo, and Honda Clarity. Maybe include a table comparing FCEVs and BEVs in terms of range, refuel time, cost, etc.

Need to ensure the language is professional but accessible. Avoid jargon without explanation. For example, explain what a fuel cell stack is. Also, check for accuracy: hydrogen production methods (like steam methane reforming vs. electrolysis), efficiency rates, and current market data.

Wait, the user specified "FCEV" as the title, so I should make sure to use that term consistently. Maybe start with an overview of FCEVs, then dive into technical details, applications, challenges, and future outlook.

I need to structure each section properly. For example, under Technical Principles, break it down into Fuel Cell System, Hydrogen Storage, Powertrain, etc. Under Challenges, maybe list infrastructure, cost, production methods, safety.

Also, include references or related documents if possible. Maybe mention other types of electric vehicles and how FCEVs differ from them.

Let me check the length requirement: at least 800 characters. The example response provided earlier was around that, so I need to make sure my content is sufficiently detailed without being redundant.

I should also verify any technical details. For instance, the efficiency of fuel cells (around 40-60% vs. BEVs' 75-90%), but FCEVs have higher energy density for long-range applications. Also, hydrogen's energy density by weight is high, but storage is a challenge due to pressure or cryogenics.

Including recent developments would add value. For example, advancements in fuel cell technology, government incentives, or new models from manufacturers.

Make sure each section flows logically. Start with an introduction, then technical aspects, applications, challenges, and future directions. Use headings appropriately, maybe H2 for main sections and H3 for subsections like "Fuel Cell Stack" under Technical Principles.

Avoid markdown in the thinking process but ensure the final answer uses proper formatting. Check for any missing information that's crucial to understanding FCEVs. Maybe include a section on environmental impact, considering hydrogen production methods.