Self-charging Lithium Batteries With New Structure

Self-charging battery successfully integrates lithium ion battery and nanogenerator into a single device hybridizing the energy conversion and energy storage into one process, which improve the total efficiency of energy conversion and energy storage. Nowadays, because of its structure, self-charging battery mainly has three problems: Low utilization rate of piezoelectric field, bigger mechanical energy loss, and low lithium storage performance of the cathode material. This thesis mainly research work is propose solutions to solve above problems. Specific studies are as follows:(1) Nanoarray piezo-anode has been used to improve the performance of self-charging lithium battery. The CuO nanoarray is obtained by wet chemical methods in situ growth on Cu film, and the CuO/PVDF nanoarray piezo-anode is obtained by spin coating method to make the PVDF coating on CuO nanoarray. And then the integrated self-charging lithium battery is obtained. Because of the closer contact and contact area between CuO electrode and PVDF separator, the internal piezo-electrochemical process makes the piezoelectric filed utilized more efficient. Integrated self-charging lithium battery can improve the performance of self-charging battery by the nanoarray piezo-anode. When the applied force is 18 N with frequency is 1.0 Hz, the capacity stored by the integrated self-charging lithium battery is 0.247 μAh within 240 s, and the stored energy is 6.12 μJ, three times of non-integrated self-charging lithium battery (stored capacity and energy is 0.0089 μAh and 1.85 μJ, respectively) at the same condition.(2) Flexible structure is used to improve the performance of self-charging lithium battery. Graphite nanosheet getted by hydrothermal process is used as anode, commercial LiCoO2 as cathode, PVDF film as piezo-seperator, sealed by EVA. And then flexible self-charging lithium battery with good flexibility is obtained. When the applied force is 34 N with frequency is 1.0 Hz, within 500 s the voltage of flexible self-charging lithium battery raised from 500 to 832 mV. The energy stored by the battery is 0.266 μAh. At the same condition, the self-charging lithium battery with steel shell structure just stored 0.031 μAh. Besides, flexible self-charging lithium battery can collect, converse and storage tiny mechanism around our living environment. By cyclic bending, finger clicking and wheel rolling, the flexible can be charged suceecssfully.(3) One-dimensional nanomaterial with core-shell is used to improve the cathode lithium storage performance of lithium battery. The FeWO4-SnO2 core-shell nanorod is obtained by hydrothermal process and wet chemistry methods. FeWO4-SnO2 core-shell nanorod as anode of lithium battery have high specific capacity and good cycle stability. The recycle capacity of FeWO4-SnO2 core-shell nanorod is 1286.9 mAh·g-1, which is far higher than FeWO4 nanorod and SnO2 nanoparticle. Due to the synergistic effect between FeWO4 and SnO2, FeWO4 after lithiation process will form W and Fe nanoparticle with unique electrochemical properties, which makes the irreversible Li2O formed in the process of SnO2 first lithiation process into reversible Li+, which significantly improves the reversible capacity.