A few years back, in a discussion with some friends, an interesting problem arose. A company my friend was working for needed some power supply for the sensor that was supposed to be used in a small shaft at some cold, scientific remote location. External conventional batteries were out of the question. I knew that tritium paint is used as “glow-in-the-dark” paint for military gun sights. I also read somewhere that European teenagers used tritium vials for their jewelry pendants.Tritium, a radioactive isotope of hydrogen with a half-life of about 12.5 years, is a relatively mild source of beta radiation. It’s so weak that it can’t even penetrate the skin. When securely enclosed within a glass vial, it poses no threat, making it a safe and viable option.An idea came to my mind: why not combine tritium vials with solar cells to create a small tritium generator that would last a decade?The solar cells I selected had peak efficiency in the orange spectrum (585–620 nanometres), so we ordered orange tritium vials. The 3D-printed enclosure was lined with solar cells, two super-capacitors were added to manage peak consumption, and voila, a long-lasting standalone power supply was created. Fast forward to the present day:Nuclear battery produces power for 50 years without needing to chargehttps://www.independent.co.uk/tech/nuclear-battery-betavolt-atomic-china-b2476979.html A Chinese startup, Beijing-based Betavolt, has unveiled a new battery using a radioactive isotope that it claims can generate electricity for 50 years without charging or maintenance.Converting energy from decaying isotopes dates back to the 20th century, with initial applications in spacecraft and remote scientific stations. Historically, these batteries were large and expensive. Still, Betavolt’s announcement marks significant progress in miniaturization and cost-effectiveness using diamond semiconductors.The principle of using diamond layers doped with radioactive isotopes is not new. Diamond is an ultrawide bandgap material with high breakdown strength, better carrier mobility, high thermal conductivity and has its use in high-power electronics.https://semiengineering.com/knowledge_centers/materials/diamond-semiconductors/ For this battery, the idea was to select an isotope that releases Beta (β⁻) particles, essentially high-energy, high-speed electrons. When these are released, the diamond matrix acts as a semiconductor to generate an electric current.Betavolt’s new battery, BV100, uses two 10-micron-thick single-crystal diamond semiconductor layers sandwiched by a 2-micron layer of Ni-63. Each sandwich can produce current, but it can also be stacked or linked like old-fashioned voltaic cells to form hundreds of independent unit modules that work together to boost the current.The whole thing is sealed in a protective case to shield against radiation exposure and to protect the battery against physical damage. The BV100, measuring 15 x 15 x 5 mm, can produce 100 microwatts at 3 volts.According to Betavolt, the BV100’s energy density is ten times that of lithium batteries and is not prone to fire or explosions. Since it generates electricity rather than stores it in the form of chemical reactions, it is not subject to recharging cycle problems. The Ni-63 eventually decays into non-radioactive copper, posing a minimal environmental risk. Here are the key technical highlights:Technical Specifications: Isotopic Power Source: The battery utilizes nickel Ni-63 isotopes to generate electricity through radioactive decay. Miniaturization: The battery module is incredibly compact, measuring just 15x15x5 cubic millimeters, making it smaller than a coin. Power Output: The current version delivers 100 microwatts of power at 3V. Future versions aim for 1 watt by 2025. Series Configuration: The small size allows for series connections to increase power output, potentially enabling continuous operation for devices like mobile phones and drones. Safety and Environmental Considerations: Safety Features: The battery’s layered design ensures it will not catch fire or explode, even under sudden force. It operates in a wide temperature range of -60°C to 120°C. Radiation Safety: Betavolt claims the battery emits no external radiation, making it safe for medical applications such as pacemakers and artificial hearts. Environmental Impact: After the decay of the nickel-63 isotopes, the resulting stable copper isotope poses no radioactive threat or environmental pollution. Conclusion:Betavolt’s innovative 100 microwatt nuclear battery and their roadmap to increase the power output to 1 watt (10,000 times increment) by 2025 are promising developments. It is definitely a remarkable leap in small-scale energy solutions.These batteries could revolutionize small, low-power devices, offering sustainable, long-lasting energy for niche applications like medical implants and sensors.However, significant obstacles still need to be addressed before it can achieve widespread practical use. For instance, typical smartphones require several watts of power for operation, far exceeding the battery’s current output. Similarly, while lower in power demand, IoT devices often need higher energy levels than presently offered. Electric vehicle usage, while widely speculated on the internet, demands exponentially more power and is currently just a pipe dream.
