Constructing ion diffusion highway in strongly coupled WSe2-carbon hybrids enables superior energy storage performance

Alkaline metal ion batteries are considered to be promising candidates in the energy storage domain, whereas the sluggish adsorption and diffusion ability by large radius of Na+/K+ constrain the large-scale application. Herein, we report the strongly coupled WSe2 with P, N dual-doped carbon nanosheets (WSe2/PNCNS) served as an anode electrode material, manifesting high specific capacities and superior cycling stability for both sodium and potassium ion storage. Theoretical calculation results demonstrate that the strongly coupled hybrids can achieve nearly zero diffusion barriers to enhance ion diffusion kinetics and adsorption energies, which could underpin the robust Na+/K+ storage capacity. Importantly, the potassium ion hybrid capacitors (KIHCs) display a high energy density of 111.9 Wh kg−1 and long cycle life with 84.9% capacity retention after 10,000 cycles. This work not only offers the guide on regulating the diffusion kinetics, but it also paves the way on practical applications for Na+/K+ storage.