The characteristics of lithium/manganese-dioxide cells using Li powder or Li foil as the negative electrode (anode) are compared at high-rate discharge. Lithium powders with a mean diameter of 20μm are produced by forming a dispersion of molten Li metal in inorganic carrier fluids. Cells using Li powder anodes show larger capacity and lower internal resistance than cells using Li foil anodes. Based on BET (Brunauer–Emmett–Teller) measurements, a reduction of effective current density due to the large surface area of the Li powder is considered to be responsible for the superior higher-rate discharge characteristics.