Construction of oxygen vacancy-rich ZnO@carbon nanofiber aerogels as a free-standing anode for superior lithium storage

The development of next-generation high-capacity freestanding materials as electrodes in lithium-ion batteries (LIBs) has significant potential. Here, oxygen vacancy-rich ZnO (O_v-ZnO) deposited on carbonized bacterial cellulose (CBC) aerogels is developed via in-situ uniformly growing ZIF-8-NH₂ particles on CBC aerogels, followed by the hydrazine reduction and pyrolysis. The CBC serves as a free-standing skeleton to disperse and support ZIF-8-NH₂ derived ZnO while the introduction of oxygen vacancies can effectively promote the internal ion/electron transfer. As a result, the obtained free-standing aerogels (O_v-ZnO@CBC) displays a reversible capacity of 710 mAh g^-1 at 1 A g^-1 after 1000 cycles, which is superior to ZnO@CBC without hydrazine reduction treatment. Furthermore, the assembled Li free-standing full cell using the O_v-ZnO@CBC composite as the anode and BC@LiFePO₄ (BC@LFP) as the cathode exhibits an outstanding cycling performance of 150 mAh g^-1 after 100 cycles at 0.1 A g^-1, displaying satisfactory lithium-ion storage capability. It is noteworthy that both O_v-ZnO@CBC and BC@LFP are obtained in the form of a free-standing aerogel. This work offers a strategy to prepare high-capacity and long-cycle self-supporting aerogel-based electrodes for flexible LIBs.