Synthesis of the layered sodium manganese nickel oxide (P2-Na0.67Mn3/4Ni1/4O2) was done by a hydroxide co-precipitation followed by mixing with sodium hydroxide and a subsequent heat-treatment in air. The co-precipitation has been performed under vigorous stirring with aqueous manganese nitrate (Carl Roth) and nickel nitrate (Carl Roth) solution, sodium hydroxide (Carl Roth) solution and ammonia solution (Carl Roth) as continuous feed-ins into a continuously stirred tank reactor (CSTR, V = 1l).