Spinel LiMn₂O₄ nanoparticles fabricated by the flexible soft template/Pichini method as cathode materials for aqueous lithium-ion capacitors with high energy and power density

Abstract

LiMn2O4 nanoparticles were synthesized by flexible Pichini method with expanded graphite as the soft template to effectively control particle size and agglomeration, contributing to high energy/power densities of its aqueous lithium-ion capacitor.

Unraveling the Mechanism and Practical Implications of the Sol-Gel Synthesis of Spinel LiMn2O4 as a Cathode Material for Li-Ion Batteries: Critical Effects of Cation Distribution at the Matrix Level

“…Small particles can improve the electrochemical performance by enhancing the Li + ion diffusion kinetics [41]; however, their high surface areas lead to a more unstable cycle life and capacity degradation after a limited number of cycles. This makes them more susceptible to phenomena such as grain growth, shrinkage, dissolution, and phase change owing to their high surface reactivity [65,66]. In addition, the Li + ions are more tightly placed at the (100) and (110) planes than at the (111) planes, indicating that the exposed (100) and (110) planes on the surface are more favorable for facilitating Li + transport kinetics [41].…”

Research Progress of LiTi2(PO4)3 Anode for Aqueous Lithium-ion Batteries

“…颗粒纳米化是提升电极材料电化学性能的重要 思路 [55][56][57][58][59] 。当材料粒径达到纳米尺度时, 能够有效缩 短 Li + 的扩散路径, 同时抑制缺陷的阻碍作用, 控制 极化现象, 另一方面, 纳米尺度的材料具有较大的 比表面积, 可以增大电极/电解液界面, 进而增加反 应活性位点, 因此颗粒纳米化可以提高材料的倍率 性能和可逆容量 [60] 。纳米尺度的 LiTi 2 (PO 4 ) 3 颗粒主 要通过溶胶-凝胶法、水热法等液相方法合成。 颗粒形貌控制是提高电极材料电性能的另一重 要思路。为获得具有特定形貌的颗粒往往需要采用 水/溶剂热法、静电纺丝法和模板法。Liang 等 [44] 采用 水热法, 在 220 ℃下保温 48 h 合成了具有规则立方 形貌的 LiTi 2 (PO 4 ) 3 , 随着时间延长和温度升高, 颗粒 的微观形貌逐渐呈现规则的方块形状, 最大颗粒接 近 50 μm。Deng 等 [61] 采用溶剂热法合成了具有规则 立方形貌的 LiTi 2 (PO 4 ) 3 , 其粒径尺寸约为 200 nm。 在 10C 倍率下, 其全电池体系 LiTi 2 (PO 4 ) 3 |1 mol•L -1 LiTFSI|LiMn 2 O 4 经 1000 次循环, 容量保持率约为 80%。Liu 等 [24] 将原料置于静电纺丝仪中, 获得了纤 维状前驱体, 经煅烧后获得 LiTi 2 (PO 4 ) 3 纤维材料, 其流程如图 4(a)所示。 与相应的颗粒材料相比, 纤维材料具有比表面 积大和长径比高等优点, 能够有效缩短 Li + 的迁移 距离, 增大材料和电解液的接触面积, 有利于电化 学反应, 展现出更优秀的倍率性能, 由图 4(b)可知, 纤维材料的倍率性能明显优于相应的颗粒材料。…”

Spinel LiMn₂O₄ Nanorods via Template–Engaged Method and as Cathode Materials for Li-Ion Batteries

“…A lot of research results show that the morphology, particle size and crystallinity of electrode materials have a very important influence to cycle performance and rate performance [8]. The 1D nanowires or nanorods can effectively offered larger specific surface area and short electronic transmission path.…”