Novel
-MnO
2 hollow urchins were synthesized on a large scale by a facile and efficient low-temperature (60
C)mild reduction route, without templates or surfactants in the system. The formation mechanism for the hollowurchins was proved to be the Ostwald ripening process by tracking the crystallization and morphology of theproduct at different reaction stages. The as-prepared hollow-urchin sample has a high Brunauer-Emmett-Tellersurface area of 132 m
2/g and a mesoporous structure, which were expected to help improve the electrochemicalproperty in Li
+ batteries. When the
-MnO
2 hollow urchins were used as the cathode material in Li batteries, theyperformed better than the other
-MnO
2 samples (solid urchins and dispersed nanorods), indicating that theelectrochemical performance of the electrode material is sensitive to its morphology. This synthetic procedure isstraightforward and inexpensive and thus facilitates mass production of
-MnO
2 hollow urchins.