3D打印柔性可穿戴锂离子电池

3D Printing of Flexible Electrodes Towards Wearable Lithium Ion Battery

利用挤出式3D打印技术制备纺织物结构的自支撑柔性锂离子电池电极的新方法,并采用高浓度的聚偏氟乙烯(PVDF)作为黏度调节剂、碳纳米管(CNT)作为导电剂、磷酸铁锂或钛酸锂作为电极活性材料,配制了具有可打印性的"墨水",其表观黏度接近105Pa·s,该"墨水"表现出明显的剪切变稀行为,同时存储模量平台值也高达105Pa,其优异的流变学性质对于打印和固化过程十分有利。电化学测试结果表明,两种打印电极具有稳定且十分匹配的充放电比容量,因此由二者组装的软包袋装全电池也具有高达~108mAh·g^(-1)的放电比容量(50mA·g^(-1)),弯曲后,在同样的电流密度下其放电比容量约为111mAh·g^(-1)。

A novel method to fabricate flexible free-standing electrodes with textile structure for lithium-ion batteries was provided by applying extrusion-based three-dimensional(3 D)printing technology.Meanwhile,highly concentrated poly(vinylidene fluoride)(PVDF)is used as viscosity modifier,carbon nanotube(CNT)as conducting additive,and lithium iron phosphate(LFP)or lithium titanium oxide(LTO)as cathode or anode active materials respectively to develop printable inks with obvious shear-thinning behavior,and with the apparent viscosity and storage modulus platform value of over105 Pa·s,which is beneficial to the printability and enable complex 3 Dstructures solidification.The electrochemical test shows that both printed electrodes have similar charge and discharge specific capacities under current density of 50 mA·g^(-1).To explore the feasibility of the printed electrodes,apouch cell with as-printed LFP and LTO electrode as cathode and anode respectively is assembled.The pouch cell without deformation delivers discharge specific capacities of approximately108 mAh·g^(-1),and there is a tiny increase in discharge specific capacities of around 111 mAh·g^(-1) for bended pouch cell.