A first electroactive material is prepared. At FIG. 5A, a solution 500 including electroactive material precursors and water is prepared. The electroactive material precursors include LiNO3, Mn(NO3)2, Ni(NO3)2 and citric acid. At FIG. 5B, The solution 500 is stirred and heated to a first temperature using a hot plate stirrer 510. The first temperature is greater than or equal to about 95° C. to less than or equal to about 100° C. After heating and stirring for a first duration of about 600 minutes, a wet, foam-like solid is formed. The wet, foam-like solid is dried at a second temperature of about 300° C. for a second duration of about 300 minutes to provide a dried foam-like solid. The dried foam-like solid is ground into a plurality of particles 520 having a particle size of about 100 nm, as shown in FIG. 3C. The particles 520 are calcined in air at a third temperature of about 900° C. for a third duration of about 20 hours to form particles of the electroactive material 530, as shown in FIG. 3D. The electroactive material 530 includes LLC including Li1.2Ni0.3Mn0.5O2.
