To achieve the 2050 carbon neutrality vision, it is necessary to promote research and development of efficient and economically beneficial green hydrogen production technologies. In the process of global transition to a low-carbon energy system, hydrogen as a key zero carbon energy carrier continues to attract much attention. This review provides a comprehensive evaluation of high-temperature solid oxide electrolysis cell technology, focusing on analyzing some related challenges and potential pathways for large-scale application.

Compared to low-temperature alternatives such as alkaline and proton exchange membrane electrolysis, SOEC has unique advantages due to its high-temperature operation, It uses ceramic materials without precious alloys and can operate at 650-1000 ℃, and it can improve the electrochemical performance, resulting in an energy conversion efficiency of > 80%, These characteristics make SOEC a promising solution for low-cost production of green hydrogen gas, The existing domestic technology is still in demonstration stage with project scales typically ranging from tens to hundreds of kilowatts. Commercial deployment needs to overcome challenges of "three highs and one low". A key is to improve power density of battery stack, increase its service life, improve system integration, and reduce costs. To solve this problem, collaborative progress is needed in fields of material innovation, structural design, and system integration.

Collaborative design approach involving electrodes, electrolytes, and sealing components is crucial in development of materials and structures. For precise microstructure control and interface optimization, battery pack can operate stably at a high current density of 2 A/cm², while controlling attenuation rate of < 1mV/h, and significantly extending actual service life.

Optimizing multi energy data collaboration system is equally crucial, and SOEC can leverage industrial waste heat and renewable energy resources to utilize medium to low temperature thermal energy (i.e., 200-300 ℃), thereby reducing external power consumption by approximately 30% and improving overall energy utilization efficiency, It is also necessary to build a regional supply chain that covers entire process from raw material and battery preparation to integrated assembly and system integration. The integration cost should be controlled within RMB 2500 kilowatt hours, and the design life should reach 50 000 h. A key is to lay a foundation for widespread application.

The widespread promotion of SOEC still faces several constraints, i.e., loss of electrode materials under high temperature and high humidity conditions, stability challenges caused due to power input fluctuations, and relatively high initial costs. Future research should focus on developing more durable electrode materials, establishing intelligent management systems that adapt to changes in renewable energy, and promoting standardization and cost control throughout entire industry chain to achieve technological popularization.

The combination of wind and solar energy with water electrolysis can build a more adaptable clean energy resource system, Integration helps alleviate grid stability issues related to intermittent renewable energy resources and significantly reduces electricity cost of hydrogen production. Hybrid wind and solar energy system can increase hydrogen production, while reducing costs. A key is that when SOEC is matched with fluctuating power sources, oxygen electrode/electrolyte interface will degrade under frequent thermal cycles, which is an important factor affecting long-term stability of system. In global, green hydrogen production driven by renewable resources is gradually known as a key approach of reducing greenhouse gas emissions. Electrolytic hydrogen can utilize local wind and solar energy to decompose water into hydrogen and oxygen, reducing production costs. Moreover, solar and wind energy are widely distributed and naturally compatible with electrolysis equipment. Excess electricity can be chemically stored as hydrogen, efficiently regulating spatial and temporal imbalance of energy supply and demand. Therefore, generated hydrogen and oxygen can be directly applied in transportation and industrial fields without conversion, making hydrogen both a primary energy source and a data carrier.

Compared with conventional methods, the SOEC technology has a better hydrogen production efficiency and a lower unit energy consumption, and its commercialization key lies in increasing lifespan of fuel cell stack from less than 10⁴ h to 5 × 10⁴ h, reducing cost of hydrogen to below $1.5/kg. The current costs of photovoltaics and wind power continue to decline. In combination with growing demand for green hydrogen in industries such as chemical metallurgy, the SOEC is expected to achieve large-scale applications in "electricity hydrogen ammonia/methanol" integrated system, distributed energy network, and sustainable financing model. Its core position lies in serving as a fundamental supporting technology for carbon neutrality goals.