Increasing demand for flexible devices in various applications, such as smart watches, healthcare, and military applications, requires the development of flexible energy-storage devices, such as lithium-ion batteries (LIBs) with high flexibility and capacity. However, it is difficult to ensure high capacity and high flexibility simultaneously through conventional electrode preparation processes. Herein, smart conductive textiles are employed as current collectors for flexible LIBs owing to their inherent flexibility, fibrous network, rough surface for better adhesion, and electrical conductivity. Conductivity and flexibility are further enhanced by nanosizing lithium titanate oxide (LTO) and lithium iron phosphate (LFP) active materials, and hybridizing them with a flexible 2D graphene template. The resulting LTO/LFP full cells demonstrate high areal capacity and flexibility with tolerance to mechanical fatigue. The battery achieves a capacity of 1.2 mA h cm while showing excellent flexibility. The cells demonstrate stable open circuit voltage retention under repeated flexing for 1000 times at a bending radius of 10 mm. The discharge capacity of the unflexed battery is retained in cells subjected to bending for 100 times at bending radii of 30, 20, and 10 mm, respectively, confirming that the suggested electrode configuration successfully prevents structural damage (delamination or cracking) upon repeated deformation.

Herein, a freestanding cellulose acetate−carbon nanotube (CA−CNT) film electrode is presented to achieve highly flexible, high-energy lithium-ion batteries (LIBs). CA serves as a dispersing agent of CNTs and a binder-free network former. A straightforward washing can remove CA in the electrode almost completely, while the fibrous CNT network within the electrode is sustained. Furthermore, the facile fabrication enables the largescale production of the film electrode because the CA−CNT film is processed by a conventional casting method and not by the arealimited vacuum filtration. The superior electrochemical performance and high flexibility of the full cell assembled with CA−CNTbased electrodes are maintained even at a high active material loading, which has been proven difficult to accomplish in the conventional configuration LIBs. In addition, by simply stacking six sheets of the freestanding film electrode, a capacity as high as 5.4 mA h cm −2 is achieved. The assembled pouch battery operates stably under extreme deformation. We demonstrate that the rational design of the electrode could extend the flexibility to a higher energy than that achieved with the conventional configuration. We believe that the low production cost, high flexibility, and superior electrochemical performance of the proposed freestanding film electrode can expedite the implementation of wearable gears in daily life.

Weavable Li-ion batteries and stretchable battery fabrics are developed based on fibrous all-in-one electrodes of carbon fiber–biological glue–active materials–membrane.

The instabilities associated with solid catalysts and carbon electrode materials are one of the challenges that prevent Li−O 2 batteries from achieving a truly rechargeable high energy density. Here, we seek to achieve reversible Li−O 2 battery operations with high energies by tackling these instabilities. Specifically, we demonstrate synergistic integration of dual soluble catalysts (2,5-di-tert-butyl-1,4-benzoquinone (DBBQ) for discharging and (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) for charging) with antimony tin oxide (ATO) noncarbon electrodes with a porous inverse opal structure. The dual soluble catalysts showed a synergistic combination without any negative interference with each other, leading to higher capacity and rechargeability. Moreover, noncarbon porous antimony tin oxide (pATO) cathodes guaranteed improved stability against catalyst degradation, while KB carbon electrodes severely threatened stability of the soluble catalysts during cycling. We also found that the surface properties of the electrodes influenced the discharge mechanism, even in the presence of a solution-phase growth promoter such as DBBQ, which implies that further interface engineering may improve the performance. This study shows the great potential of the integration of soluble catalysts with electrode materials for further improvements in capacity, energy efficiency, and rechargeability for the practical development of Li−O 2 batteries.