Applications: From Battery Materials to Sensor Systems

Insertion Electrode Materials for Rechargeable Lithium Batteries

“…9). [7,61,63,428,451±457] The so-called ªsolvated intercalationº is associated with extreme expansion of the graphite matrix (typically~150 %), frequently leading to deterioration (exfoliation) of the graphite and as a result to a drastically decreased charge storage capability. The solvated intercalation compounds are thermodynamically favored over the corresponding binary compounds, that is, the potentials of their electrochemical formation are more positive than those for the formation of the corresponding binary GICs.…”

“…2. Schematic drawing of films formed on metallic lithium in organic electrolytes (redrawn from [7]). …”

“…In the case of turbostratic carbons, their rather low specific charge is partly due to the lower number of lithium sites available in ªwrinkledº and ªbuckledº structural segments. [7,61] In addition, crosslinking of carbon sheets in disordered carbons hampers the shift to AA stacking, which is necessary for the accommodation of a higher lithium amount into graphitic sites.…”

“…This is unfavorable for the specific energy and operation of the battery. [7,50,51] Replacement of the metallic lithium by lithium insertion compounds [7,52±63] improves both cell cycle life and safety but at the expense of cell voltage, specific charge, and rate capability. If an anion-inserting polymer is used as a counterelectrode (as in Fig.…”

“…However, only the ªgraphite fluorideº (CF) n is of practical importance for primary lithium cells. [7,183,627] Li/(CF) n cells are not rechargeable because of the irreversible formation of the thermodynamically highly stable LiF at a discharge depth (lithium uptake) of about 50 % via an energetically favored displacement reaction. [628] By far the largest number of positive electrode materials that are being discussed are inorganic transition-metal oxides or sulfides.…”