The portable electronic device market is quickly outgrowing the capabilities of existing battery technology. A need for higher capacities to power new functions and enhanced features of consumer electronics is growing faster than battery energy densities can increase. Portable fuel cells are believed to be one possible solution which allows longer intervals between refueling [1]. Energy densities of various electrochemical battery and fuel cell systems are given in Table 1.1. These theoretical values are based on the active anode and cathode materials only. Other materials that may be involved in the reaction are neglected in the calculation. It should be noted that the theoretical energy densities for liquids or gases used in fuel cells exceed actual electrochemical systems of batteries by more than one order of magnitude.weiterlesen