Architecture engineering of carbonaceous anodes for high-rate potassium-ion batteries

The limited lithium resource in earth's crust has stimulated the pursuit of alternative energy storage technologies to lithium-ion battery.Potassium-ion batteries(KIBs)are regarded as a kind of promising candidate for large-scale energy storage owing to the high abundance and low cost of potassium resources.Nevertheless,further development and wide application of KIBs are still challenged by several obstacles,one of which is their fast capacity deterioration at high rates.A considerable amount of effort has recently been devoted to address this problem by developing advanced carbonaceous anode materials with diverse structures and morphologies.This review presents and highlights how the architecture engineering of carbonaceous anode materials gives rise to high-rate performances for KIBs,and also the beneficial conceptions are consciously extracted from the recent progress.Particularly,basic insights into the recent engineering strategies,structural innovation,and the related advances of carbonaceous anodes for high-rate KIBs are under specific concerns.Based on the achievements attained so far,a perspective on the foregoing,and proposed possible directions,and avenues for designing high-rate anodes,are presented finally.

Designing g-C_(3)N_(4)/N-Rich Carbon Fiber Composites for High-Performance Potassium-Ion Hybrid Capacitors

Potassium-based energy storage devices(PEDS)are considered as hopeful candidates for energy storage applications because of the abundant potassium resources in nature and high mobility in the electrolyte.although carbon materials show great potential for potassium-ion storage,poor rate performance,and unsatisfactory cycle lifespan in existing carbon-based PIBs anode,it also cannot match the dynamics and stability of the capacitor cathode.Nitrogen doping has been proven to be a effective modification strategy to improve the electrochemical performance of carbon materials.Hence,we prepare carbon nanofibers and g-C_(3)N_(4)composites with high nitrogen contents(19.78 at%);moreover,the sum of pyrrolic N and pyridinic N is up to 59.51%.It achieves high discharge capacity(391 m Ah g^(-1)at0.05 A g^(-1)),rate capacity(141 m Ah g^(-1)at 2 A g^(-1)),and long cycling performance(201 m Ah g^(-1)at 1 A g^(-1)over 3000 cycles)when as an anode for PIBs.Furthermore,it can deliver promising discharge capacity of132 m Ah g^(-1)at 0℃.Moreover,as battery anode for potassium-ion hybrid capacitors(PIHC)device with an active carbon cathode,it delivers energy/power density(62 and 2102 W kg^(-1))as well as high reversible capacity(106 m Ah g^(-1)at 1 A g^(-1)).

The homogenous growth of Co-based coordination compound on graphene nanosheet for high-performance K-organic battery and its reaction mechanism

Metal coordination compounds(MCCs)are gaining popularity for potassium-ion batteries(PIBs)owing to their tuneable structure,multiple reaction sites,low cost and unique morphology.However,they are generally subjected to intrinsic features of the sluggish ionic diffusion coefficient,low electronic conductivity and slow kinetics.Herein,a new MCC material of cobalt-1,3,5-trioxy-2,4,6-triamino-benzo(Co-TB)coordination compound was synthesized and homogenously grown on the surface of graphene nanosheets(GNS),forming a Co-TB@GNS composite with enhanced electronic conductivity and flexible capability.Benefiting from the overall enhanced conductivity,high surface area and abundant activated K-storage sites,Co-TB@GNS electrodes have exhibited superior cycling performance with high reversible capacities(312 mAh·g^(-1)after 100 cycles at 100 mA·g^(-1),224 mAh·g^(-1)after 500 cycles at 1 A·g^(-1))and better rate performances compared with the pure Co-TB compound when served as PIB's anodes.Furthermore,multiple in-situ measurement techniques have jointly confirmed that the organic functional groups(C=O,C=N and C=C of benzene rings)and Co^(2+)in Co-TB are the main reversible K-storage sites,including in-situ Fourier transform infrared spectroscopy(FTIR)and X-ray diffraction(XRD),and partial capacity contribution is originated from GNS by the apparent K-storage behavior in the in-situ XRD pattern,proving the possibility of K-storage for metal-organic materials.

Defective 1T′-ReSe2 nanosheets vertically grown on elastic MXene for fast and stable potassium ion storage

The sluggish reaction kinetics and poor structure stability of transition metal dichalcogenides(TMDs)-based anodes in potassium-ion batteries(KIBs)usually cause limited rate performance and rapid capacity decay,which seriously impede their application.Herein,we report a vacancy engineering strategy for preparing a class of Te-doped 1T'-ReSe_(2)anchored onto MXene(Te-ReSe_(2)/MXene)as an advanced anode for KIBs with high performance.By taking advantage of the synergistic effects of the defective Te-ReSe_(2)arrays with expanded interlayers and the elastic MXene nanosheets with self-autoadjustable function,the Te-ReSe_(2)/MXene superstructure exhibits boosted K^(+)ion storage performance,in terms of high reversible capacity(361.1 mA h g^(−1)at 0.1 A g^(−1)over 200 cycles),excellent rate capability(179.3 mA h g^(−1)at 20 A g^(−1)),ultra-long cycle life(202.8 mA h g^(−1)at 5 A g^(−1)over 2000 cycles),and steady operation in flexible full battery,presenting one of the best performances among the TMDs-based anodes reported thus far.The kinetics analysis and theoretical calculations further indicate that satisfactory pseudocapacitive property,high electronic conductivity and outstanding K^(+)ion adsorption/diffusion capability corroborate the accelerated reaction kinetics.Especially,structural characterizations clearly elaborate that the Te-ReSe_(2)/MXene undergoes reversible evolutions of an initial insertion process followed by a conversion reaction.