The fabrication of ultrathin films that are electrically conductive and mechanically strong for electromagnetic interference (EMI) shielding applications is challenging. Herein, ultrathin, strong, and highly flexible Ti3C2T x MXene/bacterial cellulose (BC) composite films are fabricated by a scalable in situ biosynthesis method. The Ti3C2T x MXene nanosheets are uniformly dispersed in the three-dimensional BC network to form a mechanically entangled structure that endows the MXene/BC composite films with excellent mechanical properties (tensile strength of 297.5 MPa at 25.7 wt % Ti3C2T x ) and flexibility. Importantly, a 4 μm thick Ti3C2T x /BC composite film with 76.9 wt % Ti3C2T x content demonstrates a specific EMI shielding efficiency of 29141 dB cm2 g–1, which surpasses those of most previously reported MXene-based polymer composites with similar MXene contents and carbon-based polymer composites. Our findings show that the facile, environmentally friendly, and scalable fabrication method is a promising strategy for producing ultrathin, strong, and highly flexible EMI shielding materials such as the freestanding Ti3C2T x /BC composite films for efficient EMI shielding to address EMI problems of a fast-developing modern society.

Graphene oxide-bacterial cellulose (GO/BC) nanocomposite hydrogels with well-dispersed GO in the network of BC are successfully developed using a facile one-step in situ biosynthesis by adding GO suspension into the culture medium of BC. During the biosynthesis process, the crystallinity index of BC decreases and GO is partially reduced. The experimental results indicate that GO nanosheets are uniformly dispersed and well-bound to the BC matrix and that the 3D porous structure of BC is sustained. This is responsible for efficient load transfer between the GO reinforcement and BC matrix. Compared with the pure BC, the tensile strength and Young's modulus of the GO/BC nanocomposite hydrogel containing 0.48 wt% GO are significantly improved by about 38 and 120%, respectively. The GO/BC nanocomposite hydrogels are promising as a new material for tissue engineering scaffolds.

Uniform dispersion of two-dimensional (2D) graphene materials in polymer matrices remains challenging. In this work, a novel layer-by-layer assembly strategy was developed to prepare a sophisticated nanostructure with highly dispersed 2D graphene oxide in a three-dimensional matrix consisting of one-dimensional bacterial cellulose (BC) nanofibers. This method is a breakthrough, with respect to the conventional static culture method for BC that involves multiple in situ layer-by-layer assembly steps at the interface between previously grown BC and the culture medium. In the as-prepared BC/GO nanocomposites, the GO nanosheets are mechanically bundled and chemically bonded with BC nanofibers via hydrogen bonding, forming an intriguing nanostructure. The sophisticated nanostructure of the BC/GO leads to greatly enhanced mechanical properties compared to those of bare BC. This strategy is versatile, facile, scalable, and can be promising for the development of high-performance BC-based nanocomposite hydrogels.

Conducting polyaniline (PANI) exhibits interesting properties, such as high conductivity, reversible convertibility between redox states, and advantageous structural feature. It therefore receives ever‐increasing attention for various applications. This Minireview evaluates recent studies on application of PANI for Li‐ion batteries (LIBs), Li–S batteries (LSBs) and supercapacitors (SCPs). The flexible PANI is crucial for cyclability, especially for buffering the volumetric changes of electrode materials, in addition to enhancing the electron/ion transport. Furthermore, PANI can be directly used as an electroactive component in electrode materials for LIBs or SCPs and can be widely applied in LSBs due to its physically and chemically strong affinity for S and polysulfides. The evaluation of studies herein reveals significant improvements of electrochemical performance by physical/chemical modification and incorporation of PANI.

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