Recently, the Massachusetts Institute of Technology (MIT) has made a decisive breakthrough in the field of concrete batteries-the energy density of its new concrete energy storage technology has increased 10 times compared with the original version two years ago, and the related research results have been publi shed in the Proceedings of the National Academy of Sciences (PNAS) on September 29. It marks a key step towards large-scale practical application of this technology.
Concrete, as a building material second only to water in human use, has long existed as a "plain structural material", and MIT's research team has given it the "super ability" of energy storage and perception through technological innovation. The core principle of this technology lies in the material improvement in the concrete preparation process: when adding nano-carbon black powder (the diameter is only tens of thousands of hair) when mixing cement, these nanoparticles will spontaneously polymerize to form a three-dimensional conductive network throughout the concrete, so that the original insulating concrete can be transformed into a "super capacitor" with energy storage function.
However, although the concept of the first generation of concrete batteries two years ago is novel, it is limited by the bottleneck of low energy storage density-to meet the daily electricity demand of an ordinary family, a concrete battery with a volume of 45 cubic meters is needed, which is equivalent to the basement space of a complete set of residential buildings, and it is difficult to achieve practical promotion. In order to break through this limitation, the research team used scanning electron microscopy to observe the internal structure of concrete with nanoscale precision, and found that the nano-carbon black network presented a fractal structure similar to coral, which could wrap the tiny gaps in cement to form a large number of "micro-energy storage units". Based on this discovery, the team achieved a technological leap through two key innovations:
first, optimizing the electrolyte system. The electrolyte used in the first-generation technology had low conductivity efficiency, so the team turned to organic electrolyte with better performance, which greatly improved the transmission rate of ions in the conductive network and significantly enhanced the energy storage efficiency. What is more noteworthy is that the study found that seawater can also be used as the electrolyte of the battery, providing a low-cost solution for energy storage applications in offshore wind power and other scenarios.
Second, improve the preparation process. The traditional process needs to make concrete components first, and then soak them in electrolyte, which is complex and inefficient. The new scheme directly adds electrolyte in the concrete mixing stage, which not only simplifies the production process and improves efficiency, but also prepares battery components with larger volume and higher energy storage capacity.
With the support of two innovations, the energy storage density of the new concrete battery has increased by 10 times: currently, 1 cubic meter of concrete can store more than 2 kilowatt-hours of electricity, enough to support the operation of a household refrigerator throughout the day. What's more remarkable is that the research team has verified the multi-potential of this technology through actual prototypes-they have built a small concrete arch with this material, which not only has the load-bearing capacity of conventional building components, but also successfully powers an led lamp; When pressure is applied to the arch, the led lights will flash regularly with the change of pressure, indicating that the material can sense its own pressure, realize the triple functional integration of "structural load-bearing-energy storage-stress perception", and break through the boundary between traditional building materials and functional materials. The maturity and promotion of
this technology is expected to open up a new prospect of "smart energy infrastructure": future bridges can not only supply power for their own street lights and monitoring equipment, but also monitor structural health in real time through stress sensing function, and warn through electrical signals before potential safety hazards occur; Highways can rely on concrete batteries to provide wireless charging for electric vehicle while driving, while residential buildings can store energy through walls, floors and other components to help build energy self-sufficiency. From ordinary building materials to "intelligent energy carriers", MIT's concrete battery technology is making subversive innovations to promote the deep integration of energy and infrastructure, providing new possibilities for building a green and intelligent future infrastructure system.
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