Primary batteries definitions

Figure 1. Conceptual product definitions of enzyme-based biofuel cells as they are compared in their specific energy and energy density to the existing primary battery technology. Based on Figure 2 of ref 15. Reproduced with permission. Copyright 1999 The Electrochemical Society, Inc.

Figure 1 Juxtaposes the energy fields of these three potential product definitions with that of conventional primary battery technology. The data on the energy densities for the battery product definitions were adopted from a recent technology review. The expected energy performance figures for biofuel cells...

Having two such opposite definitions is bound to cause confusion, but we note that the cathode is the correct name for the positive terminal of all primary batteries. It also helps to remember that cations are positive ions, for example, H+ is a cation. Anions are negative ions, for example, OH is an anion. It is also (rue that the cathode is always the electrode into which electrons flow, and similarly the anode is always the electrode from which electrons flow. This holds true for electrolysis, cells, valves, forward biased diodes, and fuel cells. 

Another parameter which will have a very definite bearing on the choice of battery type is cell voltage, particularly on-load voltage, which are tabulated in Table 2.1 for various types of primary battery. It can be seen that these range from 0.75V/ceJI (mercury-cadmium) to over 3 V with some of the lithium and magnesium based organic electrolyte systems. 

The complexity of quality control for proteins, as compared to small molecules, is most evident in the requirements for proof of structure. Many small molecules can be fully characterized using a few spectroscopic techniques (e.g., NMR, IR, mass spectrometry, and UV) in conjunction with an elemental analysis. However, proving the proper structure for a protein is much more complex because 1) the aforementioned spectroscopic techniques do not provide definitive structural data for proteins, and 2) protein structure includes not only molecular composition (primary structure) but additionally, secondary, tertiary, and, in some cases, quaternary features. Clearly, no single analytical test will address all of these structural aspects hence a large battery of tests is required. 

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