Electrochemical techniques have been used to study the reversible insertion
of sodium into hard-carbon host structures at room temperature. In this pa
per we compare these results with those for lithium insertion in the same m
aterials and demonstrate the presence of similar alkali;ali metal insertion
mechanisms in both cases. Despite the gravimetric capacities being lower f
or sodium than lithium insertion, we have achieved a reversible sodium capa
city of 300 mAh/g, close to that for lithium insertion in graphitic carbon
anode materials. Such materials may therefore be useful as anodes in rechar
geable sodium-ion batteries. (C) 2000 The Electrochemical Society. S0013-46
51(99)11-034-6. All rights reserved.