Effective synthesis of triphylite NaMnPO4 through acid–base reaction in aqueous solution

Abstract

Triphylite structure NaMnPO4 is expected to be an excellent candidate as the positive active material of a Na-ion battery. However, NaMnPO4 tends to generate a maricite phase that does not have a valid sodium-ion conduction path. Thus, it undergoes several complex reaction steps, such as ion exchange, to obtain the triphylite phase to have an effective sodium-ion conduction path. This study provides an effective direct synthesis method for triphylite NaMnPO4 through an acid–base reaction in aqueous solution under mild conditions.