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Larger dopants with high electron affinities are found to yield increased electrical conductivities and power factors at lower doping concentrations.

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Zinc ion batteries (ZIBs) typically work well in aqueous electrolytes. Most high-performance cathode materials of aqueous ZIBs acquire much-deteriorated capacity, voltage plateau and rate capability in organic electrolytes. It remains...

Aqueous graphite-based dual ion batteries have unique superiorities in stationary energy storage systems due to their non-transition metal configuration and safety properties. However, there is an absence of thorough study of the interactions between anions and water molecules and between anions and electrode materials, which is essential to achieve high output voltage. Here we reveal the four-stage intercalation process and energy conversion in a graphite cathode of anions with different configurations. The difference between the intercalation energy and hydration energy of bis(trifluoromethane)sulfonimide makes the best use of the electrochemical stability window of its electrolyte and delivers a high intercalation potential, while BF4− and CF3SO3− do not exhibit a satisfactory potential because the graphite intercalation potential of BF4− is inferior and the graphite intercalation potential of CF3SO3− exceeds the voltage window of its electrolyte. An aqueous dual ion battery based on the intercalation behaviors of bis(trifluoromethane)sulfonimide anions into a graphite cathode exhibits a high voltage of 2.2 V together with a specific energy of 242.74 Wh kg−1. This work provides clear guidance for the voltage plateau manipulation of anion intercalation into two-dimensional materials.

MXene-based catalysts exhibit extraordinary advantages for many catalysis reactions, such as the hydrogen evolution and oxygen reduction reactions. However, MXenes exhibit inadequate catalytic activity for the electrochemical nitrogen reduction reaction (NRR) because they are typically terminated with inactive functional groups, F* and OH*, which mask the active metal sites for N 2 binding. Here we modified the surface termination of MXene (Ti 3 C 2 T x ) nanosheets to achieve high surface catalytic reactivity for the NRR by ironing out inactive F*/OH* terminals to expose more active sites and by introducing Fe to greatly reduce the surface work function. The optimally performing catalyst (MXene/TiFeO x -700) achieved excellent Faradaic efficiency of 25.44% and an NH 3 yield rate of 2.19 μg/cm 2 •h (21.9 μg/mg cat •h), outperforming all reported MXene-based NRR catalysts. Our work provides a feasible strategy for rationally improving the surface reactivity of MXene-based catalysts for efficient electrochemical conversion of N 2 to NH 3 .

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Pseudocapacitive behavior and ion hybrid capacitors can improve the energy density of supercapacitors, but research has only considered the reaction of cations during the electrochemical process, leading to a flawed mechanistic understanding. Here, the effects of various anions carriers on the electrochemical behaviors of titanium nitride‐based zinc ion capacitor (Zn‐TiN capacitor) were explored. DFT calculations revealed the stable structure of TiN‐SO4 after adsorbed process, enabling SO42− participate in the electrochemical process and construct a two‐step adsorption and intercalation energy storage mechanism, improving the capacitance and anti‐self‐discharge ability of the Zn‐TiN capacitor, which delivered an ultrahigh capacitance of 489.8 F g−1 and retained 83.92 % of capacitance even after 500 h resting time. An energy storage system involving anions in the electrochemical process can improve capacitance and anti‐self‐discharge ability of ion hybrid capacitors.