2021 roadmap on lithium sulfur batteries by Robinson, JB, Xi, K, Kumar, RV, Ferrari, AC, Au, H, Titirici, M-M, Parra-Puerto, A, Kucernak, A, Fitch, SDS, Garcia-Araez, N, Brown, ZL, Pasta, M, Furness, L, Kibler, AJ, Walsh, DA, Johnson, LR, Holc, C, Newton, GN, Champness, NR, Markoulidis, F, Crean, C, Slade, RCT, Andritsos, EI, Cai, Q, Babar, S, Zhang, T, Lekakou, C, Kulkarni, N, Rettie, AJE, Jervis, R, Cornish, M, Marinescu, M, Offer, G, Li, Z, Bird, L, Grey, CP, Chhowalla, M, Lecce, DD, Owen, RE, Miller, TS, Brett, DJL, Liatard, S, Ainsworth, D, Shearing, PR