Although cobalt sulfide is a promising electrode material for supercapacitors, its wide application is limited by relative poor electrochemical performance, low electrical conductivity, and inefficient nanostructure. Here, we demonstrated that the electrochemical activity of cobalt sulfide could be significantly improved by Al doping. We designed and fabricated hierarchical core-branch Al-doped cobalt sulfide nanosheets anchored on Ni nanotube arrays combined with carbon cloth (denoted as CC/H-Ni@Al-Co-S) as an excellent self-standing cathode for asymmetric supercapacitors (ASCs). The combination of structural and compositional advantages endows the CC/H-Ni@Al-Co-S electrode with superior electrochemical performance with high specific capacitance (1830 F g/2434 F g at 5 mV s/1 A g) and excellent rate capability (57.2%/72.3% retention at 1000 mV s/100 A g). The corresponding all-solid-state ASCs with CC/H-Ni@Al-Co-S and multilayer graphene/CNT film as cathode and anode, respectively, achieve a high energy density up to 65.7 W h kg as well as superb cycling stability (90.6% retention after 10 000 cycles). Moreover, the ASCs also exhibit good flexibility and stability under different bending conditions. This work provides a general, effective route to prepare high-performance electrode materials for flexible all-solid-state energy storage devices.

Metal–organic frameworks (MOFs) have attracted intensive study as solid electrolytes (SEs) in recent years. However, MOF particles work separately in SEs and numerous interfaces hinder a high-efficiency ion transport, which lowers the performance of solid-state batteries (SSBs). Herein, continuous ion-conductive paths were constructed by cross-linked MOF chains. Chains of a newly developed MOF (Zr-BPDC-2SO3H) were grown on bacterial cellulose (BC) nanofibers to provide a continuous ion transport network. The cross-linked MOF chains exhibit a high ionic conductivity of 7.88 × 10–4 S cm–1 at 25 °C, single-ion transport ability (t Li +=0.88), a wide electrochemical window up to 5.10 V, excellent interface compatibility, and the capability for suppressing lithium dendrites. Most importantly, the SSB fabricated with the cross-linked MOF chains shows more than 100% improved specific capacity in comparison to an SSB without this design and stable cycling performance at 3 C. This work provides a splendid strategy for developing high-performance SEs with porous ion conductors.

Two-dimensional molybdenum disulfide (MoS2) is a promising electrode material for supercapacitors, attributing to attractive physical properties, outstanding electrical properties, and ultrahigh exposed surface area. However, MoS2 bulk suffers from low capacity due to the overlaying of the layers and the poor electric conductivity. Covalent functionalization of MoS2 is a promising, yet challenging, approach to overcome the drawbacks and boost electrochemical performance. Here, we report a series of sandwich-like 4-aminophenyl functionalized MoS2/polyaniline (MoS2–NH2/PANI) nanosheets by in situ growth of PANI on MoS2–NH2 templates. The optimized MoS2–NH2/PANI nanosheets express a high capacitance of 326.4 F g–1 at 0.5 A g–1 and a superior rate retention of 63.1% when the current density increased from 0.5 A g–1 to 1000 A g–1 in a three-electrode system. Impressively, the corresponding symmetric supercapacitors deliver an electrochemical cycling stability with 96.5% retention after 10000 cycles at 5 A g–1. Our strategy of covalent linking PANI onto functional MoS2 provides a feasible approach to improve the electrochemical performance of MoS2-based materials for energy storage.

Metal–organic frameworks (MOFs) have been attracting a great deal of attention as potential solid electrolytes (SEs). However, the interfacial compatibility of MOF-based SEs caused by the physical contact among MOF particles, the polymer binder, and electrodes is not yet fully determined. Herein, a bioinspired design strategy aiming to build ion transport pathways at interfaces was introduced. The MOF-to-MOF transport paths were built via in situ ring opening of epoxide, akin to the protein molecules that transport the ion across the cell walls. After optimization, the obtained SE is endowed with a high ion conductivity of 1.70 × 10–3 S cm–1 at 30 °C, a wide electrochemical window of 4.6 V, a high Li+ transference number of 0.8, and a decreased interface resistance. Consequently, the fabricated quasi-solid metal batteries exhibit higher and more stable cycling performance compared to the performance of those without interface optimization. This strategy for optimizing the interfacial compatibility of MOFs thus exploits a new avenue for developing high-performance SEs for various metal batteries.

The energy density of aqueous asymmetric supercapacitors (ASCs) is usually limited by low potential windows and capacitances of both anode and cathode. Herein, a facile strategy to fabricate hierarchical carbon‐coated porous vanadium nitride nanosheet arrays on vertically aligned carbon walls (CC/CW/p‐VN@C) as anode for aqueous ASCs is reported. The potential window of CC/CW/p‐VN@C electrode can be stably extended to –1.3 to 0 V (vs Ag/AgCl) with greatly improved specific capacitance (604.8 F g −1 at 1 A g −1 ), excellent rate capability (368 F g −1 at 60 A g −1 ), and remarkable electrochemical stability. To construct ASCs, a Birnessite Na 0.5 MnO 2 nanosheet arrays (CC/CW/Na 0.5 MnO 2 ) cathode is similarly built. Benefiting from the matchable potential windows and high specific capacitances of the rationally designed anode and cathode, aqueous CC/CW/p‐VN@C||CC/CW/Na 0.5 MnO 2 ASCs with a wide voltage window of 2.6 V are fabricated. Moreover, the ASCs showcase an ultrahigh energy density up to 96.7 W h kg −1 at a high power density of 1294 W kg −1 , and excellent cycling stability (92.5% retention after 10 000 cycles), outperforming most of previously reported ASCs and even comparable to that of organic electrolyte supercapacitors (SCs). This efficient strategy for fabricating 2.6 V aqueous ASCs suggests a promising research system for high energy density SCs.