Introducing a conductive pillar: a polyaniline intercalated layered titanate for high-rate and ultra-stable sodium and potassium ion storage.

A novel electrode material, TiO2-coated polyaniline intercalated layered titanate, is synthesized. Polyaniline is tri-functional: stabilizing the layered titanate structure, enlarging the interlayer spacing and enhancing the electronic conductivity. Such a composite can deliver high capacities of 258 and 219 mA h g-1 in sodium and potassium-ion batteries, respectively.

In situ carbon coated flower-like VPO as an anode material for potassium-ion batteries.

Here we design a novel carbon coating method for phosphate-based VPO4 with three different morphologies, via the intercalation of isobutanol to layered VOPO4·2H2O combined with thermal reduction. The well-constructed flower-like VPO4 delivers a high reversible capacity of 400 mA h g-1 with a long cycle-life of more than 500 cycles, proving that the special structure is suitable to accommodate the large volume expansion during the electrochemical charge-discharge process.

A vanadium-based metal-organic phosphate framework material K[(VO)(HPO)(CO)] as a cathode for potassium-ion batteries.

Herein, we report a layered material K2[(VO)2(HPO4)2(C2O4)] with a large interplanar lattice spacing. Highly reversible K+ extraction and insertion in the layers are achieved, with a good cycling stability of up to 200 cycles (83% of retention). And the structural evolution of this material during the electrochemical processes is explored.