The Effect of Controlling Strategies of pH and Ammonia Concentration on Preparing Full Concentration Gradient Ni0.8Co0.1Mn0.1(OH)2 via Coprecipitation in a Pilot‐Scale Reactor. Issue 5 (13th March 2020)

• Record Type: Journal Article
• Authors: Duan, Jihai; Zhang, Ruchao; Zhu, Quanhong; Xiao, Hang; Huang, Qingshan
• Is Part Of: Energy technology. Volume 8:Issue 5(2020:May)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-03-13
• Subjects: alloys -- full concentration gradients -- layered compounds -- Li-ion batteries -- Ni0.8Co0.1Mn0.1(OH)2; Energy development -- Periodicals; Power resources -- Periodicals; 333.79
• DOI: 10.1002/ente.201901437
• Languages: English
• ISSNs: 2194-4288

Abstract

Abstract : Full concentration gradient (FCG)‐Ni1− x − y Co x Mn y (OH)2 is generally synthesized via varying the molar ratio of metal ions in feeding flow during coprecipitation. Accordingly, pH and [N] (ammonia concentration) should change with the reaction time given that the optimum pH and [N] are different with variations of x or y . Hence, the effect of the controlling strategies of pH and [N] on preparing the FCG‐precursor is explored, and the mechanism behind is revealed. The FCG‐precursor with the covariation of pH and [N] has the densest and firmest structure, highest tap density (2.115 g mL −1 ), and a well‐ordered layered crystal structure. In addition, its discharge capacity can reach as high as 189.4 mAh g −1 (capacity retention of 96.3%) after 200 cycles at 1 C rate, which is 9.1% and 15.8% higher than FCG‐NCM811 with constant pH, [N], and Homo‐NCM811. The match between pH and [N] is crucial to obtain the favorable FCG‐precursor and ‐NCM811. Abstract : The effect of pH and [N] control on preparing full concentration gradient (FCG)‐Ni0.8 Co0.1 Mn0.1 (OH)2 is studied. It is critical to vary pH and [N] as per the ratio of metal ions in the feeding. Variation of pH and [N] favors the formation of dense and firm secondary particles and facilitates the formation of thick and flat primary particles.