Carbonization-free wood electrode with MXene-reconstructed porous structure for all-wood eco-supercapacitors

Abstract

To bypass the conventional high temperature carbonization, MXene with an ultra-high electrical conductivity and good electrochemical activity is coated on natural wood to make it a free-standing electrode (TW). TW achieves a high electrical conductivity of 106.4 S m−1 and large capacitance of ~700 mF cm−2 at 0.5 mA cm−2. Furthermore, to overcome the low space utilization of the oversized vessels in wood which leads to a low energy density, a reconstructing strategy is used on TW to fully use the natural porous structure of wood by filling MXene aerogels in vessels. Compared with TW, the MXene aerogel-loaded TW shows higher electrical conductivity of 323.6 S m−1 and capacitance of 930 mF cm−2 with remarkably high rate capability of 88.2% (0.5–10 mA cm−2). Additionally, an all-wood eco-supercapacitor is fabricated, and achieves a high energy density of 23 μW h cm−2 at 577 μW cm−2. (Figure presented.).