Li storage and Na storage in carbon materials analyzed by NMR

Solid state nuclear magnetic resonance (NMR) is a powerful tool to characterize carbon materials. The state of lithium in the anode (negative electrode) of lithium ion batteries (LIBs) has been analyzed using 7Li NMR. A 23Na NMR study on sodium stored in the hard carbon anode of a sodium ion battery (SIB) was also made and compared with the result of 7Li NMR studies of LIB. Lithium forms quasimetallic clusters in the nanopores of hard carbon whereas sodium does not. Recent developments in in situ 7Li NMR research by some groups are also introduced. In situ NMR measurements of a LIB system can reveal the non-equilibrium state of the battery during charge and discharge. [TANSO 2014 (No. 263) 104–8.]