Leading companies including Toyota, Canon, Canon, Sony, and Panasonic are developing bio battery. The bio battery creates electric energy from glucose. It is rather inexpensive because it does not need platinum, and it does not emit carbon dioxide. By adding electrolyte, it is possible to let the bio battery create electric energy continuously. The bio battery seems to be the ultimate battery for vehicles. Sony is taking the lead in this field.
The mechanism of the bio battery is simple. Human changes sugar to energy for his activities. Likewise, the bio battery changes sugar to electric energy. Adding glucose to the electrode on which enzyme is fixed allows the enzyme to resolve glucose and creates electric energy. The critical issues are the know-how on how to coat enzyme on the electrode and how to modify the surface of the electrode for higher efficiency. Sony achieved the density of electric output of 10 mW per square centimeter. However, 10 mW is the power that can marginally run a motor. Unless the density is increased to 5-10 times, it is hardly possible to put the current bio battery into practical use.
At the present stage, only glucose is feasible for bio battery. The companies involved in the development of bio battery are considering using wood and plant stalks resolvable into cellulose that has the same composition as glucose. Currently, it is not easy to reduce the production cost of a fuel battery because it needs platinum for its electrode. As a company that launched a lithium-ion battery for the first time in the world in the 1990s, Sony exerts lots of energy to make a bio battery the post lithium-ion battery and invites attention to its development activities from the world.