Pen-Tung Sah Micro-Nano Science and Technology Institute, Xiamen University , Xiamen, Fujian 361005, China.
ACS Appl Mater Interfaces. 2017 Jul 12;9(27):22641-22651. doi: 10.1021/acsami.7b07283. Epub 2017 Jun 28.
We report the synthesis and properties of a low-density (∼5 mg/cm) and highly porous (99.6% void space) three-dimensional reduced graphene oxide (rGO)/poly(acrylic acid) (PAA) nanocomposite aerogel as the scaffold for cathode materials in lithium-ion batteries (LIBs). The rGO-PAA is both simple and starts from readily available graphite and PAA, thereby providing a scalable fabrication procedure. The scaffold can support as much as a 75 mg/cm loading of LiFePO (LFP) in a ∼430 μm thick layer, and the porosity of the aerogel is tunable by compression; the flexible aerogel can be compressed 30-fold (i.e., to as little as 3.3% of its initial volume) while retaining its mechanical integrity. Replacement of the Al foil by the rGO-PAA current collector of the slurry-cast LFP (1.45 ± 0.2 g/cm tap density) provides for exemplary mass loadings of 9 mg/cm at 70 μm thickness and 1.4 g/cm density or 16 mg/cm at 100 μm thickness and ∼1.6 g/cm density. When compared to Al foil, the distribution of LFP throughout the three-dimensional rGO-PAA framework doubles the effective LFP solution-contacted area at 9 mg/cm loading and increases it 2.5-fold at 16 mg/cm loading. Overall, the rGO-PAA current collector increases the volumetric capacity by increasing the effective electrode area without compromising the electrode density, which was compromised in past research where the effective electrode area has been increased by reducing the particle size.
我们报告了一种低密度（约 5 mg/cm）和高多孔性（99.6%的空隙空间）的三维还原氧化石墨烯（rGO）/聚丙烯酸（PAA）纳米复合气凝胶作为锂离子电池（LIBs）阴极材料的支架的合成和性能。rGO-PAA 既简单又从易得的石墨和 PAA 开始，从而提供了一种可扩展的制造工艺。支架可以在 430 μm 厚的层中支撑高达 75 mg/cm 的 LiFePO（LFP）负载，并且气凝胶的多孔性可以通过压缩进行调节；柔性气凝胶可以压缩 30 倍（即，压缩到初始体积的 3.3%），同时保持其机械完整性。用 rGO-PAA 代替浆料浇铸 LFP 的 Al 箔（1.45±0.2 g/cm 振实密度）作为集流器，可实现 9 mg/cm 的出色质量负载，厚度为 70 μm，密度为 1.4 g/cm，或厚度为 100 μm，密度约为 1.6 g/cm。与 Al 箔相比，LFP 在三维 rGO-PAA 框架中的分布使有效 LFP 溶液接触面积在 9 mg/cm 负载时增加了一倍，在 16 mg/cm 负载时增加了 2.5 倍。总体而言，rGO-PAA 集流器通过增加有效电极面积而不牺牲电极密度来提高体积容量，这在过去的研究中受到了损害，其中通过减小颗粒尺寸来增加有效电极面积。
