Strategic synthesis of sponge-like structured SiO x @C@CoO multifunctional composites for high-performance and stable lithium-ion batteries

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2021-08, Vol.9 (34), p.18440-18453
• Main Authors: Wang, Pu, Sun, Zhongti, Liu, Hui, Gao, Zhi-Wen, Hu, Jianguo, Yin, Wan-Jian, Ke, Qingqing, Zhu, Hugh Lu
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/D1TA02880D

Sub-stoichiometric silicon oxide (SiO x ) is regarded as one of the most promising alternatives to silicon for use in lithium-ion batteries because of its high theoretical capacity, low cost, and abundant reserves. However, the practical application of a SiO x anode is largely limited by the inferior Li + kinetic characteristics and slow electron transport. Herein, we strategically synthesize sponge-structured SiO x @C@CoO multifunctional composites via spray drying and an electrostatic self-assembly strategy. Ultrathin CoO nanosheets are self-assembled on the surfaces of carbon coated SiO x particles (SiO x @C). The novel design can effectively improve the conductivity of SiO x , shorten the diffusion length and increase surface areas to enhance Li + diffusion; more importantly the sponge-like structure is capable of accommodating the volume change, contributing to an improved and stable electrochemical performance during the charging/discharging processes. Based on theoretical simulations, it was confirmed that SiO x @C@CoO composites can increase the adsorption energy and reduce the diffusion barrier of Li + compared with SiO x @C, which enhance the storage capacity and facilitate the Li + diffusion during cycling processes. Consequently, sponge-like structured SiO x @C@CoO multifunctional composites achieve a reversible specific capacity of up to 1287 mA h g −1 at a current density of 0.1 A g −1 , and retain 714 mA h g −1 after 750 cycles at 1 A g −1 with a capacity retention of 98.9%. Remarkably, SiO x @C@CoO composites show great potential in full lithium-ion batteries. Employing LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM 811) as the cathode, the pouch-type cell exhibits an excellent reversible capacity of 206 mA h g −1 and a long-term cycling stability with a capacity retention of 85.9% after 200 cycles.