In Situ NMR Studies of Lithium Ion Batteries

In situ nuclear magnetic resonance (NMR) has now been implemented by a number of groups and provides a non-invasive means to study electrochemically induced structural changes, as of lithium ion batteries (LIBs). Since graphitic carbon is the most common anode material in commercial Li-ion batteries, with a capacity of 372 mAh/g, it seems appropriate that the first 7Li in situ NMR studies were carried out on these electrodes. Lithium metal, by definition, must have the highest capacity of all lithium based anode materials and will also give the highest cell voltage. Silicon represents a promising anode material for lithium ion batteries, as it offers very high specific capacities of about 3600 mAh/g. Resolution will be a concern in many systems, although methods for separating different signals, based on relaxation times or possibly double resonance NMR experiments, may help to resolve the signals from different environments.