Freestanding conversion-type anode via one-pot formation for flexible Li-ion battery

Abstract

Transition metal oxide-based anodes are an attractive candidate for high performance next-generation batteries due to their high theoretical capacity. However, their practical applications toward high energy density are limited due to the inactive materials in the electrode and large volume expansion during Li insertion and extraction processes. Here, we report a one-pot formation method of cryptomelane manganese oxide nanowiresbased freestanding anode for Li-ion storage. The freestanding electrodes are completed simply by vacuum drying a controlled in-situ hydrogel thin film with no additional process, achieving flexible devices without a binder. The porous electrode structure via such a one-pot synthesis makes it capable of multidimensional Li-ion accessibility and volume change suppression. As a result, the mechanically flexible anode delivers the reversible capacity of about 525 mAh g-1 after 400th cycles at 1.0 A g-1. This study opens up the feasibility of one-pot synthesis in the design of various conversion-type electrodes to realize ultra-light, flexible energy storage devices.