Figure 3.

Comparisons of A) energy density with different types of DEGs^{[ 18} , ¹⁹ , ²⁰ , ²¹ , ²² , ²³ , ²⁴ , ²⁵ , ²⁶ , ²⁷ , ³² , ³³ , ^{34 ]} and B) charge density with different types of TENGs per cycle.^{[ 9} , ¹⁰ , ¹¹ , ¹² , ¹³ , ¹⁴ , ¹⁵ , ¹⁶ , ³¹ , ³⁵ , ³⁶ , ³⁷ , ³⁸ , ³⁹ , ^{45 ]}