纳米纤维素/MnO2自支撑锌离子电池正极的制备及其电化学性能研究

以羟基纳米纤维素为原料,利用其表面丰富的羟基还原KMnO 4,在纳米纤维表面原位生成MnO₂纳米颗粒,并与Super P混合,通过简单抽滤的方式获得CNF@MnO₂/Super P自支撑正极。结果表明:无粘结剂的CNF@MnO₂/Super P自支撑正极具有较高的循环稳定性,在0.5 A·g^-1的电流密度下,循环800圈后,容量仍能达到247 mAh·g^-1;均匀分布的纳米MnO₂与Super P能够有效缩短离子和电子扩散路径,大大降低材料的电阻,使正极具有良好的倍率性能,在2 A·g^-1的电流密度下,循环300圈之后,电池容量仍保持在175 mAh·g^-1,库仑效率~99%;利用该正极良好的延展性,制备了软包电池,并表现出了较高的循环稳定性和容量保持率,该工作为柔性无粘结剂的水系Zn-MnO₂二次电池的设计开发提供了新的研究思路。

Preparation of cellulose nanofiber/MnO2cathode for zinc ion battery and study on its electrochemical properties

KMnO 4 was reduced by hydroxyl cellulose nanofiber(CNF)with abundant hydroxyl groups on its surface.MnO₂nanoparticles were generated in situ on the surface of nanofibers.The CNF@MnO₂/Super P self-supporting cathode was prepared by simple filtration for the mixture of CNF@MnO₂and Super P.The results show that the binder free CNF@MnO₂/Super P cathode has a high cycle stability,and its capacity can still mantain 247 mAh·g^-1after 800 cycles at the current density of 0.5 A·g^-1.Uniform distribution of nano MnO₂and super P can effectively shorten the diffusion path of ions and electrons,and greatly reduce the resistance of the materials,resulting in good rate performance of cathode.The capacity of the battery remains at 175 mAh·g^-1with high coulomb efficiency(~99%)after 300 cycles at the current density of 2 A·g^-1.By utilizing the good ductility of cathode,soft package battery was prepared,which showed high cycle stability and capacity retention rate.This work provides a new research idea for the design and development of binder-free rechargeable Zn-MnO₂batteries.