The electrochemical behaviour of a Sn-based anode in a potassium cell is reported for the first time. The material is active at low potentials vs. K/K(+), and encouraging capacities of around 150 mA h g(-1) are recorded. Experimental evidence shows that Sn is capable of alloying/de-alloying with potassium in a reversible manner.

Anode materials that operate via the alloying–dealloying reaction mechanism are well known in established and maturing battery systems such as lithium‐ion and sodium‐ion batteries. Recently, a new type of metal‐ion battery that utilizes K+ ions in its operating principle has attracted significant attention due to a possibility of building high voltage cells using an abundant potassium ionic shuttle. Establishing promising electrode materials is of paramount importance for this new type of battery. This feature article summarizes available early results on the alloying–dealloying anode materials in potassium electrochemical cells. Based on original research (some data are presented for the first time) and independently published literature, experimental results on silicon, tin, phosphorus, antimony, and lead‐containing anodes are critically discussed. The electrochemical properties, charge storage mechanisms, and achievable capacities are considered. The results are compared with the behaviors of the same materials in lithium and sodium cells, and the importance of the volumetric parameters of electrodes is emphasized. Finally, a number of further research directions in these interesting anode materials are suggested. The feature article provides a useful reference for the growing number of researchers and specialists working in the field of emerging metal‐ion batteries with non‐lithium chemistries.

Potassium electrochemistry of a battery anode based on black phosphorus is reported. The phosphorus component operates via electrochemical alloying with potassium and has a theoretical capacity of 843 mA h g−1.

An anode material incorporating a sulfide is reported. SnS nanoparticles anchored onto reduced graphene oxide are produced via a chemical route and demonstrate an impressive capacity of 350 mA h g, exceeding the capacity of graphite. These results open the door for a new class of high capacity anode materials (based on sulfide chemistry) for potassium-ion batteries.

The hybridisation of CoO and FeO nanoparticles dispersed in a super P carbon matrix is proposed as a favourable approach to improve the electrochemical performance (reversible capacity, cycling stability and rate capability) of the metal oxide electrodes in metal-ion batteries. Hybrid CoO-FeO/C is prepared by a simple, cheap and easily scalable molten salt method combined with ball-milling and used in sodium-ion and potassium-ion batteries for the first time. The electrode exhibits excellent cycling stability and superior rate capability in sodium-ion cells with a capacity recovery of 440 mA h g (93% retention) after 180 long-term cycles at 50-1000 mA g and back to 50 mA g. In contrast, CoO-FeO, CoO and FeO electrodes display unsatisfactory electrochemical performance. The hybrid CoO-FeO/C is also reactive with potassium and capable of delivering a reversible capacity of 220 mA h g at 50 mA g which is comparable with the most reported anode materials for potassium-ion batteries. The obtained results broaden the range of transition metal oxide-based hybrids as potential anodes for K-ion and Na-ion batteries, and suggest that further studies of these materials with potassium and sodium are worthwhile.

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Liquid plasma, produced by nanosecond pulses, provides an efficient and simple way to fabricate a nanocomposite architecture of Co3O4/CNTs from carbon nanotubes (CNTs) and clusters of Co3O4 nanoparticles in deionized water. The crucial feature of the composite's structure is that Co3O4 nanoparticle clusters are uniformly dispersed and anchored to CNT networks in which Co3O4 guarantees high electrochemical reactivity towards sodium, and CNTs provide conductivity and stabilize the anode structure. We demonstrated that the Co3O4/CNT nanocomposite is capable of delivering a stable and high capacity of 403 mA h g(-1) at 50 mA g(-1) after 100 cycles where the sodium uptake/extract is confirmed in the way of reversible conversion reaction by adopting ex situ techniques. The rate capability of the composite is significantly improved and its reversible capacity is measured to be 212 mA h g(-1) at 1.6 A g(-1) and 190 mA h g(-1) at 3.2 A g(-1), respectively. Due to the simple synthesis technique with high electrochemical performance, Co3O4/CNT nanocomposites have great potential as anode materials for sodium-ion batteries.

. (2012). All-polymer battery system based on polypyrrole (PPy)/para (toluene sulfonic acid) (pTS) and polypyrrole (PPy)/indigo carmine (IC) free standing films. Electrochimica Acta, 83 209-215.All-polymer battery system based on polypyrrole (PPy)/para (toluene sulfonic acid) (pTS) and polypyrrole (PPy)/indigo carmine (IC) free standing films AbstractIn this study, we introduce a novel all-polymer battery system based on conducting polymer (polypyrrole, PPy) doped with dopants of para (toluene sulfonic acid) (pTS) and indigo carmine (IC), respectively. The performance of the systems consisting of polypyrrole-para (toluene sulfonic acid) (PPy-pTS) as cathode and polypyrrole-indigo carmine (PPy-IC) as anode in conjunction with either a polymer based electrolyte or a commercial organic electrolyte of 1M LiPF 6 in a 50:50 (v/v) mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) was evaluated. In the system, all the free-standing PPy-pTS and PPy-IC films were directly used without needing any metal substrate support to hold the electro active material. Electrochemical measurements demonstrated that the PPy-pTS/PPy-IC (commercial electrolyte) system exhibited a reversible discharge capacity of 36 mAh g -1 at 0.05 mA cm -2 after 50 cycles, is 92% of the initial discharge capacity. In the case of PPy-pTS/PPy-IC (polymer electrolyte), the reversible discharge capacity after 50 cycles was 16 mAh g -1 , 76% of the intial discharge capacity. This work deals with the fabrication of a novel all polymer battery system, with significant advantages in terms of capacity and reasonable stability. This may lead to a future generation of all polymer batteries that are suitable for implanted medical devices used in biological and biomedical systems. (c) 2012 Elsevier Ltd. All rights reserved. AbstractIn this present study, we introduce a novel all-polymer battery system based on conducting polymer (polypyrrole, PPy) doped with redox-active compounds of para (toluene sulfonic acid) (pTS) and indigo carmine (IC), respectively. The performance of the systems consisting of polypyrrole-para (toluene sulfonic acid) (PPy-pTS) as cathode and polypyrrole-indigo carmine (PPy-IC) as anode in conjunction with gel polymer electrolyte and commercial electrolyte of 1M LiPF 6 are evaluated. In the system, all the free-standing PPy-pTS and PPy-IC films were directly used without need any metal substrate to act as an electrical conductor.Electrochemical measurements demonstrated that the PPy-pTS/PPy-IC (commercial electrolyte) system exhibited a discharge capacity of 36 mAh g -1 at 0.05 mA cm -2 after 50 cycles, which is around 92 % of the initial discharge capacity. In the case of PPy-pTS/PPy-IC (polymer electrolyte), the discharge capacity retention was 16 mAh g -1 , which is also 76 % of the intial discharge capacity. The capacity degradation rate was calculated only 0.16 and 0.48 %/cycle for the PPy-pTS/PPy-IC (commercial electrolyte) and PPy-pTS/PPy-IC (polymer electrolyte) system, respectively, confirming stable cycling performance...