"Free-from": transition metal-free and anode-free potassium batteries

Energy storage plays a pivotal role in bring all greenhouse gas (GHG) emissions to net zero by 2050. The International Energy Agency (IEA) estimated that an additional 310 GW of grid-connected electricity storage would be needed to support electricity sector decarbonisation. Thus, battery technology is becoming a prominent slice of energy research portfolio in the UK. Li-ion battery (LIB) has certainly been a contender, as reflected by the enormous UKRI investments and research effort devoted to LIBs. However, the large share of LIB industry on the demand for Li and Co will result in supply risk in near future and expose the UK to external market and geopolitical forces; hence, the heavy focus on Li battery chemistry is not sustainable.

Sustainable decarbonisation calls for immediate investigation on adventurous battery technologies that will have large economic and environmental rewards. This project aims at high-risk research on developing an adventurous battery technology - transition metal-free and anode-free potassium batteries using sulphur-selenium chemistry. The proposed battery technology is environmentally friendly and cost-effective because (i) it does not contain any transition metals (such as Co and Ni) or expensive metals (such as Cu); it is based on abundant and cheap elements (K, Al, S and Se). It is also scientifically exciting and innovative because it is anode-free, which solves the fundamental limitation of huge metal excess in metal anode batteries and will deliver a step-change improvement in energy density. In addition, S-Se chemistry will provide high K inventory (further contributing to improving energy density) and power density. Furthermore, the proposed battery technology can be deployed in a manner compatible with the context of circular economy via (i) a low eco-impact of battery materials and the minimization of battery recycling procedure due to the absence of transition metals, (ii) reducing the risk of a high reactivity leading to exothermal oxidation due to the absence of an alkali metal anode, and (iii) lowering energy consumption to separate Al and Cu during battery recycling due to the absence of Al. Therefore, the outcome of this project will direct a promising avenue of sustainable decarbonisation via decentralised electricity generation by renewable
sources and scalable energy storage and deployment.

The activities included in the project are: (i) explore an anode-free configuration of battery cells; (ii) design surface modification of Al current collector to achieve stable electrochemical K stripping/plating; (iii) perform in-situ and ex-situ characterisations to best characterise, understand and explain the electrochemical process of storing K via S-Se cathode chemistry; (iv) design a "breathable" carbon host to engineer cathode architecture; (v) coordinate surface-modified Al current collector and architecturally engineered cathode to deliver a demonstrator cell; (vi) engage with the public and be an advocate for sustainable decarbonisation and adventurous energy solutions.